diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2019-07-20 10:45:15 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-07-20 10:45:15 -0700 |
commit | e6023adc5c6af79ac8ac5b17939f58091fa0d870 (patch) | |
tree | a6092129571a51fca4e06b7278ff5d6cfb009b7e | |
parent | 4b01f5a4c9c4f0c502875c1fb31dcd5d0df86475 (diff) | |
parent | b68b9907069a8d3a65bc16a35360bf8f8603c8fa (diff) |
Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull core fixes from Thomas Gleixner:
- A collection of objtool fixes which address recent fallout partially
exposed by newer toolchains, clang, BPF and general code changes.
- Force USER_DS for user stack traces
[ Note: the "objtool fixes" are not all to objtool itself, but for
kernel code that triggers objtool warnings.
Things like missing function size annotations, or code that confuses
the unwinder etc. - Linus]
* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (27 commits)
objtool: Support conditional retpolines
objtool: Convert insn type to enum
objtool: Fix seg fault on bad switch table entry
objtool: Support repeated uses of the same C jump table
objtool: Refactor jump table code
objtool: Refactor sibling call detection logic
objtool: Do frame pointer check before dead end check
objtool: Change dead_end_function() to return boolean
objtool: Warn on zero-length functions
objtool: Refactor function alias logic
objtool: Track original function across branches
objtool: Add mcsafe_handle_tail() to the uaccess safe list
bpf: Disable GCC -fgcse optimization for ___bpf_prog_run()
x86/uaccess: Remove redundant CLACs in getuser/putuser error paths
x86/uaccess: Don't leak AC flag into fentry from mcsafe_handle_tail()
x86/uaccess: Remove ELF function annotation from copy_user_handle_tail()
x86/head/64: Annotate start_cpu0() as non-callable
x86/entry: Fix thunk function ELF sizes
x86/kvm: Don't call kvm_spurious_fault() from .fixup
x86/kvm: Replace vmx_vmenter()'s call to kvm_spurious_fault() with UD2
...
-rw-r--r-- | arch/x86/entry/thunk_64.S | 5 | ||||
-rw-r--r-- | arch/x86/include/asm/kvm_host.h | 34 | ||||
-rw-r--r-- | arch/x86/include/asm/paravirt.h | 1 | ||||
-rw-r--r-- | arch/x86/kernel/head_64.S | 4 | ||||
-rw-r--r-- | arch/x86/kernel/kvm.c | 1 | ||||
-rw-r--r-- | arch/x86/kvm/emulate.c | 44 | ||||
-rw-r--r-- | arch/x86/kvm/vmx/vmenter.S | 6 | ||||
-rw-r--r-- | arch/x86/lib/copy_user_64.S | 2 | ||||
-rw-r--r-- | arch/x86/lib/getuser.S | 20 | ||||
-rw-r--r-- | arch/x86/lib/putuser.S | 29 | ||||
-rw-r--r-- | arch/x86/lib/usercopy_64.c | 2 | ||||
-rw-r--r-- | include/linux/compiler-gcc.h | 2 | ||||
-rw-r--r-- | include/linux/compiler.h | 5 | ||||
-rw-r--r-- | include/linux/compiler_types.h | 4 | ||||
-rw-r--r-- | kernel/bpf/core.c | 5 | ||||
-rw-r--r-- | kernel/stacktrace.c | 5 | ||||
-rw-r--r-- | tools/objtool/arch.h | 36 | ||||
-rw-r--r-- | tools/objtool/arch/x86/decode.c | 2 | ||||
-rw-r--r-- | tools/objtool/check.c | 333 | ||||
-rw-r--r-- | tools/objtool/check.h | 3 | ||||
-rw-r--r-- | tools/objtool/elf.c | 8 | ||||
-rw-r--r-- | tools/objtool/elf.h | 5 |
22 files changed, 311 insertions, 245 deletions
diff --git a/arch/x86/entry/thunk_64.S b/arch/x86/entry/thunk_64.S index cfdca8b42c70..cc20465b2867 100644 --- a/arch/x86/entry/thunk_64.S +++ b/arch/x86/entry/thunk_64.S @@ -12,9 +12,7 @@ /* rdi: arg1 ... normal C conventions. rax is saved/restored. */ .macro THUNK name, func, put_ret_addr_in_rdi=0 - .globl \name - .type \name, @function -\name: + ENTRY(\name) pushq %rbp movq %rsp, %rbp @@ -35,6 +33,7 @@ call \func jmp .L_restore + ENDPROC(\name) _ASM_NOKPROBE(\name) .endm diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 0cc5b611a113..8282b8d41209 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1496,25 +1496,29 @@ enum { #define kvm_arch_vcpu_memslots_id(vcpu) ((vcpu)->arch.hflags & HF_SMM_MASK ? 1 : 0) #define kvm_memslots_for_spte_role(kvm, role) __kvm_memslots(kvm, (role).smm) +asmlinkage void __noreturn kvm_spurious_fault(void); + /* * Hardware virtualization extension instructions may fault if a * reboot turns off virtualization while processes are running. - * Trap the fault and ignore the instruction if that happens. + * Usually after catching the fault we just panic; during reboot + * instead the instruction is ignored. */ -asmlinkage void kvm_spurious_fault(void); - -#define ____kvm_handle_fault_on_reboot(insn, cleanup_insn) \ - "666: " insn "\n\t" \ - "668: \n\t" \ - ".pushsection .fixup, \"ax\" \n" \ - "667: \n\t" \ - cleanup_insn "\n\t" \ - "cmpb $0, kvm_rebooting \n\t" \ - "jne 668b \n\t" \ - __ASM_SIZE(push) " $666b \n\t" \ - "jmp kvm_spurious_fault \n\t" \ - ".popsection \n\t" \ - _ASM_EXTABLE(666b, 667b) +#define ____kvm_handle_fault_on_reboot(insn, cleanup_insn) \ + "666: \n\t" \ + insn "\n\t" \ + "jmp 668f \n\t" \ + "667: \n\t" \ + "call kvm_spurious_fault \n\t" \ + "668: \n\t" \ + ".pushsection .fixup, \"ax\" \n\t" \ + "700: \n\t" \ + cleanup_insn "\n\t" \ + "cmpb $0, kvm_rebooting\n\t" \ + "je 667b \n\t" \ + "jmp 668b \n\t" \ + ".popsection \n\t" \ + _ASM_EXTABLE(666b, 700b) #define __kvm_handle_fault_on_reboot(insn) \ ____kvm_handle_fault_on_reboot(insn, "") diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h index c25c38a05c1c..d6f5ae2c79ab 100644 --- a/arch/x86/include/asm/paravirt.h +++ b/arch/x86/include/asm/paravirt.h @@ -746,6 +746,7 @@ bool __raw_callee_save___native_vcpu_is_preempted(long cpu); PV_RESTORE_ALL_CALLER_REGS \ FRAME_END \ "ret;" \ + ".size " PV_THUNK_NAME(func) ", .-" PV_THUNK_NAME(func) ";" \ ".popsection") /* Get a reference to a callee-save function */ diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index bcd206c8ac90..66b4a7757397 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -253,10 +253,10 @@ END(secondary_startup_64) * start_secondary() via .Ljump_to_C_code. */ ENTRY(start_cpu0) - movq initial_stack(%rip), %rsp UNWIND_HINT_EMPTY + movq initial_stack(%rip), %rsp jmp .Ljump_to_C_code -ENDPROC(start_cpu0) +END(start_cpu0) #endif /* Both SMP bootup and ACPI suspend change these variables */ diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index 82caf01b63dd..6661bd2f08a6 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -838,6 +838,7 @@ asm( "cmpb $0, " __stringify(KVM_STEAL_TIME_preempted) "+steal_time(%rax);" "setne %al;" "ret;" +".size __raw_callee_save___kvm_vcpu_is_preempted, .-__raw_callee_save___kvm_vcpu_is_preempted;" ".popsection"); #endif diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 8e409ad448f9..718f7d9afedc 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -312,29 +312,42 @@ static void invalidate_registers(struct x86_emulate_ctxt *ctxt) static int fastop(struct x86_emulate_ctxt *ctxt, void (*fop)(struct fastop *)); -#define FOP_FUNC(name) \ +#define __FOP_FUNC(name) \ ".align " __stringify(FASTOP_SIZE) " \n\t" \ ".type " name ", @function \n\t" \ name ":\n\t" -#define FOP_RET "ret \n\t" +#define FOP_FUNC(name) \ + __FOP_FUNC(#name) + +#define __FOP_RET(name) \ + "ret \n\t" \ + ".size " name ", .-" name "\n\t" + +#define FOP_RET(name) \ + __FOP_RET(#name) #define FOP_START(op) \ extern void em_##op(struct fastop *fake); \ asm(".pushsection .text, \"ax\" \n\t" \ ".global em_" #op " \n\t" \ - FOP_FUNC("em_" #op) + ".align " __stringify(FASTOP_SIZE) " \n\t" \ + "em_" #op ":\n\t" #define FOP_END \ ".popsection") +#define __FOPNOP(name) \ + __FOP_FUNC(name) \ + __FOP_RET(name) + #define FOPNOP() \ - FOP_FUNC(__stringify(__UNIQUE_ID(nop))) \ - FOP_RET + __FOPNOP(__stringify(__UNIQUE_ID(nop))) #define FOP1E(op, dst) \ - FOP_FUNC(#op "_" #dst) \ - "10: " #op " %" #dst " \n\t" FOP_RET + __FOP_FUNC(#op "_" #dst) \ + "10: " #op " %" #dst " \n\t" \ + __FOP_RET(#op "_" #dst) #define FOP1EEX(op, dst) \ FOP1E(op, dst) _ASM_EXTABLE(10b, kvm_fastop_exception) @@ -366,8 +379,9 @@ static int fastop(struct x86_emulate_ctxt *ctxt, void (*fop)(struct fastop *)); FOP_END #define FOP2E(op, dst, src) \ - FOP_FUNC(#op "_" #dst "_" #src) \ - #op " %" #src ", %" #dst " \n\t" FOP_RET + __FOP_FUNC(#op "_" #dst "_" #src) \ + #op " %" #src ", %" #dst " \n\t" \ + __FOP_RET(#op "_" #dst "_" #src) #define FASTOP2(op) \ FOP_START(op) \ @@ -405,8 +419,9 @@ static int fastop(struct x86_emulate_ctxt *ctxt, void (*fop)(struct fastop *)); FOP_END #define FOP3E(op, dst, src, src2) \ - FOP_FUNC(#op "_" #dst "_" #src "_" #src2) \ - #op " %" #src2 ", %" #src ", %" #dst " \n\t" FOP_RET + __FOP_FUNC(#op "_" #dst "_" #src "_" #src2) \ + #op " %" #src2 ", %" #src ", %" #dst " \n\t"\ + __FOP_RET(#op "_" #dst "_" #src "_" #src2) /* 3-operand, word-only, src2=cl */ #define FASTOP3WCL(op) \ @@ -423,7 +438,7 @@ static int fastop(struct x86_emulate_ctxt *ctxt, void (*fop)(struct fastop *)); ".type " #op ", @function \n\t" \ #op ": \n\t" \ #op " %al \n\t" \ - FOP_RET + __FOP_RET(#op) asm(".pushsection .fixup, \"ax\"\n" ".global kvm_fastop_exception \n" @@ -449,7 +464,10 @@ FOP_SETCC(setle) FOP_SETCC(setnle) FOP_END; -FOP_START(salc) "pushf; sbb %al, %al; popf \n\t" FOP_RET +FOP_START(salc) +FOP_FUNC(salc) +"pushf; sbb %al, %al; popf \n\t" +FOP_RET(salc) FOP_END; /* diff --git a/arch/x86/kvm/vmx/vmenter.S b/arch/x86/kvm/vmx/vmenter.S index d4cb1945b2e3..4010d519eb8c 100644 --- a/arch/x86/kvm/vmx/vmenter.S +++ b/arch/x86/kvm/vmx/vmenter.S @@ -54,9 +54,9 @@ ENTRY(vmx_vmenter) ret 3: cmpb $0, kvm_rebooting - jne 4f - call kvm_spurious_fault -4: ret + je 4f + ret +4: ud2 .pushsection .fixup, "ax" 5: jmp 3b diff --git a/arch/x86/lib/copy_user_64.S b/arch/x86/lib/copy_user_64.S index 378a1f70ae7d..4fe1601dbc5d 100644 --- a/arch/x86/lib/copy_user_64.S +++ b/arch/x86/lib/copy_user_64.S @@ -239,7 +239,7 @@ copy_user_handle_tail: ret _ASM_EXTABLE_UA(1b, 2b) -ENDPROC(copy_user_handle_tail) +END(copy_user_handle_tail) /* * copy_user_nocache - Uncached memory copy with exception handling diff --git a/arch/x86/lib/getuser.S b/arch/x86/lib/getuser.S index 74fdff968ea3..304f958c27b2 100644 --- a/arch/x86/lib/getuser.S +++ b/arch/x86/lib/getuser.S @@ -115,29 +115,29 @@ ENDPROC(__get_user_8) EXPORT_SYMBOL(__get_user_8) +bad_get_user_clac: + ASM_CLAC bad_get_user: xor %edx,%edx mov $(-EFAULT),%_ASM_AX - ASM_CLAC ret -END(bad_get_user) #ifdef CONFIG_X86_32 +bad_get_user_8_clac: + ASM_CLAC bad_get_user_8: xor %edx,%edx xor %ecx,%ecx mov $(-EFAULT),%_ASM_AX - ASM_CLAC ret -END(bad_get_user_8) #endif - _ASM_EXTABLE_UA(1b, bad_get_user) - _ASM_EXTABLE_UA(2b, bad_get_user) - _ASM_EXTABLE_UA(3b, bad_get_user) + _ASM_EXTABLE_UA(1b, bad_get_user_clac) + _ASM_EXTABLE_UA(2b, bad_get_user_clac) + _ASM_EXTABLE_UA(3b, bad_get_user_clac) #ifdef CONFIG_X86_64 - _ASM_EXTABLE_UA(4b, bad_get_user) + _ASM_EXTABLE_UA(4b, bad_get_user_clac) #else - _ASM_EXTABLE_UA(4b, bad_get_user_8) - _ASM_EXTABLE_UA(5b, bad_get_user_8) + _ASM_EXTABLE_UA(4b, bad_get_user_8_clac) + _ASM_EXTABLE_UA(5b, bad_get_user_8_clac) #endif diff --git a/arch/x86/lib/putuser.S b/arch/x86/lib/putuser.S index d2e5c9c39601..14bf78341d3c 100644 --- a/arch/x86/lib/putuser.S +++ b/arch/x86/lib/putuser.S @@ -32,8 +32,6 @@ */ #define ENTER mov PER_CPU_VAR(current_task), %_ASM_BX -#define EXIT ASM_CLAC ; \ - ret .text ENTRY(__put_user_1) @@ -43,7 +41,8 @@ ENTRY(__put_user_1) ASM_STAC 1: movb %al,(%_ASM_CX) xor %eax,%eax - EXIT + ASM_CLAC + ret ENDPROC(__put_user_1) EXPORT_SYMBOL(__put_user_1) @@ -56,7 +55,8 @@ ENTRY(__put_user_2) ASM_STAC 2: movw %ax,(%_ASM_CX) xor %eax,%eax - EXIT + ASM_CLAC + ret ENDPROC(__put_user_2) EXPORT_SYMBOL(__put_user_2) @@ -69,7 +69,8 @@ ENTRY(__put_user_4) ASM_STAC 3: movl %eax,(%_ASM_CX) xor %eax,%eax - EXIT + ASM_CLAC + ret ENDPROC(__put_user_4) EXPORT_SYMBOL(__put_user_4) @@ -85,19 +86,21 @@ ENTRY(__put_user_8) 5: movl %edx,4(%_ASM_CX) #endif xor %eax,%eax - EXIT + ASM_CLAC + RET ENDPROC(__put_user_8) EXPORT_SYMBOL(__put_user_8) +bad_put_user_clac: + ASM_CLAC bad_put_user: movl $-EFAULT,%eax - EXIT -END(bad_put_user) + RET - _ASM_EXTABLE_UA(1b, bad_put_user) - _ASM_EXTABLE_UA(2b, bad_put_user) - _ASM_EXTABLE_UA(3b, bad_put_user) - _ASM_EXTABLE_UA(4b, bad_put_user) + _ASM_EXTABLE_UA(1b, bad_put_user_clac) + _ASM_EXTABLE_UA(2b, bad_put_user_clac) + _ASM_EXTABLE_UA(3b, bad_put_user_clac) + _ASM_EXTABLE_UA(4b, bad_put_user_clac) #ifdef CONFIG_X86_32 - _ASM_EXTABLE_UA(5b, bad_put_user) + _ASM_EXTABLE_UA(5b, bad_put_user_clac) #endif diff --git a/arch/x86/lib/usercopy_64.c b/arch/x86/lib/usercopy_64.c index e0e006f1624e..fff28c6f73a2 100644 --- a/arch/x86/lib/usercopy_64.c +++ b/arch/x86/lib/usercopy_64.c @@ -60,7 +60,7 @@ EXPORT_SYMBOL(clear_user); * but reuse __memcpy_mcsafe in case a new read error is encountered. * clac() is handled in _copy_to_iter_mcsafe(). */ -__visible unsigned long +__visible notrace unsigned long mcsafe_handle_tail(char *to, char *from, unsigned len) { for (; len; --len, to++, from++) { diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index e8579412ad21..d7ee4c6bad48 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -170,3 +170,5 @@ #else #define __diag_GCC_8(s) #endif + +#define __no_fgcse __attribute__((optimize("-fno-gcse"))) diff --git a/include/linux/compiler.h b/include/linux/compiler.h index 8aaf7cd026b0..f0fd5636fddb 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -116,9 +116,14 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val, ".pushsection .discard.unreachable\n\t" \ ".long 999b - .\n\t" \ ".popsection\n\t" + +/* Annotate a C jump table to allow objtool to follow the code flow */ +#define __annotate_jump_table __section(".rodata..c_jump_table") + #else #define annotate_reachable() #define annotate_unreachable() +#define __annotate_jump_table #endif #ifndef ASM_UNREACHABLE diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h index 095d55c3834d..599c27b56c29 100644 --- a/include/linux/compiler_types.h +++ b/include/linux/compiler_types.h @@ -189,6 +189,10 @@ struct ftrace_likely_data { #define asm_volatile_goto(x...) asm goto(x) #endif +#ifndef __no_fgcse +# define __no_fgcse +#endif + /* Are two types/vars the same type (ignoring qualifiers)? */ #define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b)) diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 16079550db6d..8191a7db2777 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -1295,11 +1295,11 @@ bool bpf_opcode_in_insntable(u8 code) * * Decode and execute eBPF instructions. */ -static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn, u64 *stack) +static u64 __no_fgcse ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn, u64 *stack) { #define BPF_INSN_2_LBL(x, y) [BPF_##x | BPF_##y] = &&x##_##y #define BPF_INSN_3_LBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = &&x##_##y##_##z - static const void *jumptable[256] = { + static const void * const jumptable[256] __annotate_jump_table = { [0 ... 255] = &&default_label, /* Now overwrite non-defaults ... */ BPF_INSN_MAP(BPF_INSN_2_LBL, BPF_INSN_3_LBL), @@ -1558,7 +1558,6 @@ out: BUG_ON(1); return 0; } -STACK_FRAME_NON_STANDARD(___bpf_prog_run); /* jump table */ #define PROG_NAME(stack_size) __bpf_prog_run##stack_size #define DEFINE_BPF_PROG_RUN(stack_size) \ diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c index e6a02b274b73..f5440abb7532 100644 --- a/kernel/stacktrace.c +++ b/kernel/stacktrace.c @@ -226,12 +226,17 @@ unsigned int stack_trace_save_user(unsigned long *store, unsigned int size) .store = store, .size = size, }; + mm_segment_t fs; /* Trace user stack if not a kernel thread */ if (current->flags & PF_KTHREAD) return 0; + fs = get_fs(); + set_fs(USER_DS); arch_stack_walk_user(consume_entry, &c, task_pt_regs(current)); + set_fs(fs); + return c.len; } #endif diff --git a/tools/objtool/arch.h b/tools/objtool/arch.h index 580e344db3dd..ced3765c4f44 100644 --- a/tools/objtool/arch.h +++ b/tools/objtool/arch.h @@ -11,22 +11,24 @@ #include "elf.h" #include "cfi.h" -#define INSN_JUMP_CONDITIONAL 1 -#define INSN_JUMP_UNCONDITIONAL 2 -#define INSN_JUMP_DYNAMIC 3 -#define INSN_CALL 4 -#define INSN_CALL_DYNAMIC 5 -#define INSN_RETURN 6 -#define INSN_CONTEXT_SWITCH 7 -#define INSN_STACK 8 -#define INSN_BUG 9 -#define INSN_NOP 10 -#define INSN_STAC 11 -#define INSN_CLAC 12 -#define INSN_STD 13 -#define INSN_CLD 14 -#define INSN_OTHER 15 -#define INSN_LAST INSN_OTHER +enum insn_type { + INSN_JUMP_CONDITIONAL, + INSN_JUMP_UNCONDITIONAL, + INSN_JUMP_DYNAMIC, + INSN_JUMP_DYNAMIC_CONDITIONAL, + INSN_CALL, + INSN_CALL_DYNAMIC, + INSN_RETURN, + INSN_CONTEXT_SWITCH, + INSN_STACK, + INSN_BUG, + INSN_NOP, + INSN_STAC, + INSN_CLAC, + INSN_STD, + INSN_CLD, + INSN_OTHER, +}; enum op_dest_type { OP_DEST_REG, @@ -68,7 +70,7 @@ void arch_initial_func_cfi_state(struct cfi_state *state); int arch_decode_instruction(struct elf *elf, struct section *sec, unsigned long offset, unsigned int maxlen, - unsigned int *len, unsigned char *type, + unsigned int *len, enum insn_type *type, unsigned long *immediate, struct stack_op *op); bool arch_callee_saved_reg(unsigned char reg); diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c index 584568f27a83..0567c47a91b1 100644 --- a/tools/objtool/arch/x86/decode.c +++ b/tools/objtool/arch/x86/decode.c @@ -68,7 +68,7 @@ bool arch_callee_saved_reg(unsigned char reg) int arch_decode_instruction(struct elf *elf, struct section *sec, unsigned long offset, unsigned int maxlen, - unsigned int *len, unsigned char *type, + unsigned int *len, enum insn_type *type, unsigned long *immediate, struct stack_op *op) { struct insn insn; diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 172f99195726..5f26620f13f5 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -18,6 +18,8 @@ #define FAKE_JUMP_OFFSET -1 +#define C_JUMP_TABLE_SECTION ".rodata..c_jump_table" + struct alternative { struct list_head list; struct instruction *insn; @@ -95,6 +97,20 @@ static struct instruction *next_insn_same_func(struct objtool_file *file, for (insn = next_insn_same_sec(file, insn); insn; \ insn = next_insn_same_sec(file, insn)) +static bool is_sibling_call(struct instruction *insn) +{ + /* An indirect jump is either a sibling call or a jump to a table. */ + if (insn->type == INSN_JUMP_DYNAMIC) + return list_empty(&insn->alts); + + if (insn->type != INSN_JUMP_CONDITIONAL && + insn->type != INSN_JUMP_UNCONDITIONAL) + return false; + + /* add_jump_destinations() sets insn->call_dest for sibling calls. */ + return !!insn->call_dest; +} + /* * This checks to see if the given function is a "noreturn" function. * @@ -103,14 +119,9 @@ static struct instruction *next_insn_same_func(struct objtool_file *file, * * For local functions, we have to detect them manually by simply looking for * the lack of a return instruction. - * - * Returns: - * -1: error - * 0: no dead end - * 1: dead end */ -static int __dead_end_function(struct objtool_file *file, struct symbol *func, - int recursion) +static bool __dead_end_function(struct objtool_file *file, struct symbol *func, + int recursion) { int i; struct instruction *insn; @@ -136,30 +147,33 @@ static int __dead_end_function(struct objtool_file *file, struct symbol *func, "rewind_stack_do_exit", }; + if (!func) + return false; + if (func->bind == STB_WEAK) - return 0; + return false; if (func->bind == STB_GLOBAL) for (i = 0; i < ARRAY_SIZE(global_noreturns); i++) if (!strcmp(func->name, global_noreturns[i])) - return 1; + return true; if (!func->len) - return 0; + return false; insn = find_insn(file, func->sec, func->offset); if (!insn->func) - return 0; + return false; func_for_each_insn_all(file, func, insn) { empty = false; if (insn->type == INSN_RETURN) - return 0; + return false; } if (empty) - return 0; + return false; /* * A function can have a sibling call instead of a return. In that @@ -167,40 +181,31 @@ static int __dead_end_function(struct objtool_file *file, struct symbol *func, * of the sibling call returns. */ func_for_each_insn_all(file, func, insn) { - if (insn->type == INSN_JUMP_UNCONDITIONAL) { + if (is_sibling_call(insn)) { struct instruction *dest = insn->jump_dest; if (!dest) /* sibling call to another file */ - return 0; - - if (dest->func && dest->func->pfunc != insn->func->pfunc) { + return false; - /* local sibling call */ - if (recursion == 5) { - /* - * Infinite recursion: two functions - * have sibling calls to each other. - * This is a very rare case. It means - * they aren't dead ends. - */ - return 0; - } - - return __dead_end_function(file, dest->func, - recursion + 1); + /* local sibling call */ + if (recursion == 5) { + /* + * Infinite recursion: two functions have + * sibling calls to each other. This is a very + * rare case. It means they aren't dead ends. + */ + return false; } - } - if (insn->type == INSN_JUMP_DYNAMIC && list_empty(&insn->alts)) - /* sibling call */ - return 0; + return __dead_end_function(file, dest->func, recursion+1); + } } - return 1; + return true; } -static int dead_end_function(struct objtool_file *file, struct symbol *func) +static bool dead_end_function(struct objtool_file *file, struct symbol *func) { return __dead_end_function(file, func, 0); } @@ -262,19 +267,12 @@ static int decode_instructions(struct objtool_file *file) if (ret) goto err; - if (!insn->type || insn->type > INSN_LAST) { - WARN_FUNC("invalid instruction type %d", - insn->sec, insn->offset, insn->type); - ret = -1; - goto err; - } - hash_add(file->insn_hash, &insn->hash, insn->offset); list_add_tail(&insn->list, &file->insn_list); } list_for_each_entry(func, &sec->symbol_list, list) { - if (func->type != STT_FUNC) + if (func->type != STT_FUNC || func->alias != func) continue; if (!find_insn(file, sec, func->offset)) { @@ -284,8 +282,7 @@ static int decode_instructions(struct objtool_file *file) } func_for_each_insn(file, func, insn) - if (!insn->func) - insn->func = func; + insn->func = func; } } @@ -488,6 +485,7 @@ static const char *uaccess_safe_builtin[] = { /* misc */ "csum_partial_copy_generic", "__memcpy_mcsafe", + "mcsafe_handle_tail", "ftrace_likely_update", /* CONFIG_TRACE_BRANCH_PROFILING */ NULL }; @@ -505,7 +503,7 @@ static void add_uaccess_safe(struct objtool_file *file) if (!func) continue; - func->alias->uaccess_safe = true; + func->uaccess_safe = true; } } @@ -577,13 +575,16 @@ static int add_jump_destinations(struct objtool_file *file) * Retpoline jumps are really dynamic jumps in * disguise, so convert them accordingly. */ - insn->type = INSN_JUMP_DYNAMIC; + if (insn->type == INSN_JUMP_UNCONDITIONAL) + insn->type = INSN_JUMP_DYNAMIC; + else + insn->type = INSN_JUMP_DYNAMIC_CONDITIONAL; + insn->retpoline_safe = true; continue; } else { - /* sibling call */ + /* external sibling call */ insn->call_dest = rela->sym; - insn->jump_dest = NULL; continue; } @@ -623,7 +624,7 @@ static int add_jump_destinations(struct objtool_file *file) * However this code can't completely replace the * read_symbols() code because this doesn't detect the * case where the parent function's only reference to a - * subfunction is through a switch table. + * subfunction is through a jump table. */ if (!strstr(insn->func->name, ".cold.") && strstr(insn->jump_dest->func->name, ".cold.")) { @@ -633,9 +634,8 @@ static int add_jump_destinations(struct objtool_file *file) } else if (insn->jump_dest->func->pfunc != insn->func->pfunc && insn->jump_dest->offset == insn->jump_dest->func->offset) { - /* sibling class */ + /* internal sibling call */ insn->call_dest = insn->jump_dest->func; - insn->jump_dest = NULL; } } } @@ -896,20 +896,26 @@ out: return ret; } -static int add_switch_table(struct objtool_file *file, struct instruction *insn, - struct rela *table, struct rela *next_table) +static int add_jump_table(struct objtool_file *file, struct instruction *insn, + struct rela *table) { struct rela *rela = table; - struct instruction *alt_insn; + struct instruction *dest_insn; struct alternative *alt; struct symbol *pfunc = insn->func->pfunc; unsigned int prev_offset = 0; - list_for_each_entry_from(rela, &table->rela_sec->rela_list, list) { - if (rela == next_table) + /* + * Each @rela is a switch table relocation which points to the target + * instruction. + */ + list_for_each_entry_from(rela, &table->sec->rela_list, list) { + + /* Check for the end of the table: */ + if (rela != table && rela->jump_table_start) break; - /* Make sure the switch table entries are consecutive: */ + /* Make sure the table entries are consecutive: */ if (prev_offset && rela->offset != prev_offset + 8) break; @@ -918,12 +924,12 @@ static int add_switch_table(struct objtool_file *file, struct instruction *insn, rela->addend == pfunc->offset) break; - alt_insn = find_insn(file, rela->sym->sec, rela->addend); - if (!alt_insn) + dest_insn = find_insn(file, rela->sym->sec, rela->addend); + if (!dest_insn) break; - /* Make sure the jmp dest is in the function or subfunction: */ - if (alt_insn->func->pfunc != pfunc) + /* Make sure the destination is in the same function: */ + if (!dest_insn->func || dest_insn->func->pfunc != pfunc) break; alt = malloc(sizeof(*alt)); @@ -932,7 +938,7 @@ static int add_switch_table(struct objtool_file *file, struct instruction *insn, return -1; } - alt->insn = alt_insn; + alt->insn = dest_insn; list_add_tail(&alt->list, &insn->alts); prev_offset = rela->offset; } @@ -947,7 +953,7 @@ static int add_switch_table(struct objtool_file *file, struct instruction *insn, } /* - * find_switch_table() - Given a dynamic jump, find the switch jump table in + * find_jump_table() - Given a dynamic jump, find the switch jump table in * .rodata associated with it. * * There are 3 basic patterns: @@ -989,13 +995,13 @@ static int add_switch_table(struct objtool_file *file, struct instruction *insn, * * NOTE: RETPOLINE made it harder still to decode dynamic jumps. */ -static struct rela *find_switch_table(struct objtool_file *file, +static struct rela *find_jump_table(struct objtool_file *file, struct symbol *func, struct instruction *insn) { - struct rela *text_rela, *rodata_rela; + struct rela *text_rela, *table_rela; struct instruction *orig_insn = insn; - struct section *rodata_sec; + struct section *table_sec; unsigned long table_offset; /* @@ -1028,42 +1034,52 @@ static struct rela *find_switch_table(struct objtool_file *file, continue; table_offset = text_rela->addend; - rodata_sec = text_rela->sym->sec; + table_sec = text_rela->sym->sec; if (text_rela->type == R_X86_64_PC32) table_offset += 4; /* * Make sure the .rodata address isn't associated with a - * symbol. gcc jump tables are anonymous data. + * symbol. GCC jump tables are anonymous data. + * + * Also support C jump tables which are in the same format as + * switch jump tables. For objtool to recognize them, they + * need to be placed in the C_JUMP_TABLE_SECTION section. They + * have symbols associated with them. */ - if (find_symbol_containing(rodata_sec, table_offset)) + if (find_symbol_containing(table_sec, table_offset) && + strcmp(table_sec->name, C_JUMP_TABLE_SECTION)) continue; - rodata_rela = find_rela_by_dest(rodata_sec, table_offset); - if (rodata_rela) { - /* - * Use of RIP-relative switch jumps is quite rare, and - * indicates a rare GCC quirk/bug which can leave dead - * code behind. - */ - if (text_rela->type == R_X86_64_PC32) - file->ignore_unreachables = true; + /* Each table entry has a rela associated with it. */ + table_rela = find_rela_by_dest(table_sec, table_offset); + if (!table_rela) + continue; - return rodata_rela; - } + /* + * Use of RIP-relative switch jumps is quite rare, and + * indicates a rare GCC quirk/bug which can leave dead code + * behind. + */ + if (text_rela->type == R_X86_64_PC32) + file->ignore_unreachables = true; + + return table_rela; } return NULL; } - -static int add_func_switch_tables(struct objtool_file *file, - struct symbol *func) +/* + * First pass: Mark the head of each jump table so that in the next pass, + * we know when a given jump table ends and the next one starts. + */ +static void mark_func_jump_tables(struct objtool_file *file, + struct symbol *func) { - struct instruction *insn, *last = NULL, *prev_jump = NULL; - struct rela *rela, *prev_rela = NULL; - int ret; + struct instruction *insn, *last = NULL; + struct rela *rela; func_for_each_insn_all(file, func, insn) { if (!last) @@ -1071,7 +1087,7 @@ static int add_func_switch_tables(struct objtool_file *file, /* * Store back-pointers for unconditional forward jumps such - * that find_switch_table() can back-track using those and + * that find_jump_table() can back-track using those and * avoid some potentially confusing code. */ if (insn->type == INSN_JUMP_UNCONDITIONAL && insn->jump_dest && @@ -1086,27 +1102,25 @@ static int add_func_switch_tables(struct objtool_file *file, if (insn->type != INSN_JUMP_DYNAMIC) continue; - rela = find_switch_table(file, func, insn); - if (!rela) - continue; - - /* - * We found a switch table, but we don't know yet how big it - * is. Don't add it until we reach the end of the function or - * the beginning of another switch table in the same function. - */ - if (prev_jump) { - ret = add_switch_table(file, prev_jump, prev_rela, rela); - if (ret) - return ret; + rela = find_jump_table(file, func, insn); + if (rela) { + rela->jump_table_start = true; + insn->jump_table = rela; } - - prev_jump = insn; - prev_rela = rela; } +} + +static int add_func_jump_tables(struct objtool_file *file, + struct symbol *func) +{ + struct instruction *insn; + int ret; - if (prev_jump) { - ret = add_switch_table(file, prev_jump, prev_rela, NULL); + func_for_each_insn_all(file, func, insn) { + if (!insn->jump_table) + continue; + + ret = add_jump_table(file, insn, insn->jump_table); if (ret) return ret; } @@ -1119,7 +1133,7 @@ static int add_func_switch_tables(struct objtool_file *file, * section which contains a list of addresses within the function to jump to. * This finds these jump tables and adds them to the insn->alts lists. */ -static int add_switch_table_alts(struct objtool_file *file) +static int add_jump_table_alts(struct objtool_file *file) { struct section *sec; struct symbol *func; @@ -1133,7 +1147,8 @@ static int add_switch_table_alts(struct objtool_file *file) if (func->type != STT_FUNC) continue; - ret = add_func_switch_tables(file, func); + mark_func_jump_tables(file, func); + ret = add_func_jump_tables(file, func); if (ret) return ret; } @@ -1277,13 +1292,18 @@ static void mark_rodata(struct objtool_file *file) bool found = false; /* - * This searches for the .rodata section or multiple .rodata.func_name - * sections if -fdata-sections is being used. The .str.1.1 and .str.1.8 - * rodata sections are ignored as they don't contain jump tables. + * Search for the following rodata sections, each of which can + * potentially contain jump tables: + * + * - .rodata: can contain GCC switch tables + * - .rodata.<func>: same, if -fdata-sections is being used + * - .rodata..c_jump_table: contains C annotated jump tables + * + * .rodata.str1.* sections are ignored; they don't contain jump tables. */ for_each_sec(file, sec) { - if (!strncmp(sec->name, ".rodata", 7) && - !strstr(sec->name, ".str1.")) { + if ((!strncmp(sec->name, ".rodata", 7) && !strstr(sec->name, ".str1.")) || + !strcmp(sec->name, C_JUMP_TABLE_SECTION)) { sec->rodata = true; found = true; } @@ -1325,7 +1345,7 @@ static int decode_sections(struct objtool_file *file) if (ret) return ret; - ret = add_switch_table_alts(file); + ret = add_jump_table_alts(file); if (ret) return ret; @@ -1873,12 +1893,12 @@ static bool insn_state_match(struct instruction *insn, struct insn_state *state) static inline bool func_uaccess_safe(struct symbol *func) { if (func) - return func->alias->uaccess_safe; + return func->uaccess_safe; return false; } -static inline const char *insn_dest_name(struct instruction *insn) +static inline const char *call_dest_name(struct instruction *insn) { if (insn->call_dest) return insn->call_dest->name; @@ -1890,13 +1910,13 @@ static int validate_call(struct instruction *insn, struct insn_state *state) { if (state->uaccess && !func_uaccess_safe(insn->call_dest)) { WARN_FUNC("call to %s() with UACCESS enabled", - insn->sec, insn->offset, insn_dest_name(insn)); + insn->sec, insn->offset, call_dest_name(insn)); return 1; } if (state->df) { WARN_FUNC("call to %s() with DF set", - insn->sec, insn->offset, insn_dest_name(insn)); + insn->sec, insn->offset, call_dest_name(insn)); return 1; } @@ -1920,13 +1940,12 @@ static int validate_sibling_call(struct instruction *insn, struct insn_state *st * each instruction and validate all the rules described in * tools/objtool/Documentation/stack-validation.txt. */ -static int validate_branch(struct objtool_file *file, struct instruction *first, - struct insn_state state) +static int validate_branch(struct objtool_file *file, struct symbol *func, + struct instruction *first, struct insn_state state) { struct alternative *alt; struct instruction *insn, *next_insn; struct section *sec; - struct symbol *func = NULL; int ret; insn = first; @@ -1947,9 +1966,6 @@ static int validate_branch(struct objtool_file *file, struct instruction *first, return 1; } - if (insn->func) - func = insn->func->pfunc; - if (func && insn->ignore) { WARN_FUNC("BUG: why am I validating an ignored function?", sec, insn->offset); @@ -1971,7 +1987,7 @@ static int validate_branch(struct objtool_file *file, struct instruction *first, i = insn; save_insn = NULL; - func_for_each_insn_continue_reverse(file, insn->func, i) { + func_for_each_insn_continue_reverse(file, func, i) { if (i->save) { save_insn = i; break; @@ -2017,7 +2033,7 @@ static int validate_branch(struct objtool_file *file, struct instruction *first, if (alt->skip_orig) skip_orig = true; - ret = validate_branch(file, alt->insn, state); + ret = validate_branch(file, func, alt->insn, state); if (ret) { if (backtrace) BT_FUNC("(alt)", insn); @@ -2055,7 +2071,7 @@ static int validate_branch(struct objtool_file *file, struct instruction *first, if (state.bp_scratch) { WARN("%s uses BP as a scratch register", - insn->func->name); + func->name); return 1; } @@ -2067,36 +2083,28 @@ static int validate_branch(struct objtool_file *file, struct instruction *first, if (ret) return ret; - if (insn->type == INSN_CALL) { - if (is_fentry_call(insn)) - break; - - ret = dead_end_function(file, insn->call_dest); - if (ret == 1) - return 0; - if (ret == -1) - return 1; - } - - if (!no_fp && func && !has_valid_stack_frame(&state)) { + if (!no_fp && func && !is_fentry_call(insn) && + !has_valid_stack_frame(&state)) { WARN_FUNC("call without frame pointer save/setup", sec, insn->offset); return 1; } + + if (dead_end_function(file, insn->call_dest)) + return 0; + break; case INSN_JUMP_CONDITIONAL: case INSN_JUMP_UNCONDITIONAL: - if (func && !insn->jump_dest) { + if (func && is_sibling_call(insn)) { ret = validate_sibling_call(insn, &state); if (ret) return ret; - } else if (insn->jump_dest && - (!func || !insn->jump_dest->func || - insn->jump_dest->func->pfunc == func)) { - ret = validate_branch(file, insn->jump_dest, - state); + } else if (insn->jump_dest) { + ret = validate_branch(file, func, + insn->jump_dest, state); if (ret) { if (backtrace) BT_FUNC("(branch)", insn); @@ -2110,13 +2118,17 @@ static int validate_branch(struct objtool_file *file, struct instruction *first, break; case INSN_JUMP_DYNAMIC: - if (func && list_empty(&insn->alts)) { + case INSN_JUMP_DYNAMIC_CONDITIONAL: + if (func && is_sibling_call(insn)) { ret = validate_sibling_call(insn, &state); if (ret) return ret; } - return 0; + if (insn->type == INSN_JUMP_DYNAMIC) + return 0; + + break; case INSN_CONTEXT_SWITCH: if (func && (!next_insn || !next_insn->hint)) { @@ -2162,7 +2174,7 @@ static int validate_branch(struct objtool_file *file, struct instruction *first, break; case INSN_CLAC: - if (!state.uaccess && insn->func) { + if (!state.uaccess && func) { WARN_FUNC("redundant UACCESS disable", sec, insn->offset); return 1; } @@ -2183,7 +2195,7 @@ static int validate_branch(struct objtool_file *file, struct instruction *first, break; case INSN_CLD: - if (!state.df && insn->func) + if (!state.df && func) WARN_FUNC("redundant CLD", sec, insn->offset); state.df = false; @@ -2222,7 +2234,7 @@ static int validate_unwind_hints(struct objtool_file *file) for_each_insn(file, insn) { if (insn->hint && !insn->visited) { - ret = validate_branch(file, insn, state); + ret = validate_branch(file, insn->func, insn, state); if (ret && backtrace) BT_FUNC("<=== (hint)", insn); warnings += ret; @@ -2345,16 +2357,25 @@ static int validate_functions(struct objtool_file *file) for_each_sec(file, sec) { list_for_each_entry(func, &sec->symbol_list, list) { - if (func->type != STT_FUNC || func->pfunc != func) + if (func->type != STT_FUNC) + continue; + + if (!func->len) { + WARN("%s() is missing an ELF size annotation", + func->name); + warnings++; + } + + if (func->pfunc != func || func->alias != func) continue; insn = find_insn(file, sec, func->offset); - if (!insn || insn->ignore) + if (!insn || insn->ignore || insn->visited) continue; - state.uaccess = func->alias->uaccess_safe; + state.uaccess = func->uaccess_safe; - ret = validate_branch(file, insn, state); + ret = validate_branch(file, func, insn, state); if (ret && backtrace) BT_FUNC("<=== (func)", insn); warnings += ret; @@ -2407,7 +2428,7 @@ int check(const char *_objname, bool orc) objname = _objname; - file.elf = elf_open(objname, orc ? O_RDWR : O_RDONLY); + file.elf = elf_read(objname, orc ? O_RDWR : O_RDONLY); if (!file.elf) return 1; diff --git a/tools/objtool/check.h b/tools/objtool/check.h index cb60b9acf5cf..b881fafcf55d 100644 --- a/tools/objtool/check.h +++ b/tools/objtool/check.h @@ -31,13 +31,14 @@ struct instruction { struct section *sec; unsigned long offset; unsigned int len; - unsigned char type; + enum insn_type type; unsigned long immediate; bool alt_group, visited, dead_end, ignore, hint, save, restore, ignore_alts; bool retpoline_safe; struct symbol *call_dest; struct instruction *jump_dest; struct instruction *first_jump_src; + struct rela *jump_table; struct list_head alts; struct symbol *func; struct stack_op stack_op; diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c index e99e1be19ad9..edba4745f25a 100644 --- a/tools/objtool/elf.c +++ b/tools/objtool/elf.c @@ -278,7 +278,7 @@ static int read_symbols(struct elf *elf) } if (sym->offset == s->offset) { - if (sym->len == s->len && alias == sym) + if (sym->len && sym->len == s->len && alias == sym) alias = s; if (sym->len >= s->len) { @@ -385,7 +385,7 @@ static int read_relas(struct elf *elf) rela->offset = rela->rela.r_offset; symndx = GELF_R_SYM(rela->rela.r_info); rela->sym = find_symbol_by_index(elf, symndx); - rela->rela_sec = sec; + rela->sec = sec; if (!rela->sym) { WARN("can't find rela entry symbol %d for %s", symndx, sec->name); @@ -401,7 +401,7 @@ static int read_relas(struct elf *elf) return 0; } -struct elf *elf_open(const char *name, int flags) +struct elf *elf_read(const char *name, int flags) { struct elf *elf; Elf_Cmd cmd; @@ -463,7 +463,7 @@ struct section *elf_create_section(struct elf *elf, const char *name, { struct section *sec, *shstrtab; size_t size = entsize * nr; - struct Elf_Scn *s; + Elf_Scn *s; Elf_Data *data; sec = malloc(sizeof(*sec)); diff --git a/tools/objtool/elf.h b/tools/objtool/elf.h index e44ca5d51871..44150204db4d 100644 --- a/tools/objtool/elf.h +++ b/tools/objtool/elf.h @@ -57,11 +57,12 @@ struct rela { struct list_head list; struct hlist_node hash; GElf_Rela rela; - struct section *rela_sec; + struct section *sec; struct symbol *sym; unsigned int type; unsigned long offset; int addend; + bool jump_table_start; }; struct elf { @@ -74,7 +75,7 @@ struct elf { }; -struct elf *elf_open(const char *name, int flags); +struct elf *elf_read(const char *name, int flags); struct section *find_section_by_name(struct elf *elf, const char *name); struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset); struct symbol *find_symbol_by_name(struct elf *elf, const char *name); |