diff options
| author | Conor Dooley <conor.dooley@microchip.com> | 2023-02-12 19:47:36 +0000 |
|---|---|---|
| committer | Palmer Dabbelt <palmer@rivosinc.com> | 2023-02-21 17:21:33 -0800 |
| commit | 9493e6f3ce02f44c21aa19f3cbf3b9aa05479d06 (patch) | |
| tree | 54164a2ac5364380d1abd992413ca3aa086fa6e0 | |
| parent | dac8bf14bb49aecd1de99ebb5498fa03152f2d40 (diff) | |
RISC-V: take text_mutex during alternative patching
Guenter reported a splat during boot, that Samuel pointed out was the
lockdep assertion failing in patch_insn_write():
WARNING: CPU: 0 PID: 0 at arch/riscv/kernel/patch.c:63 patch_insn_write+0x222/0x2f6
epc : patch_insn_write+0x222/0x2f6
ra : patch_insn_write+0x21e/0x2f6
epc : ffffffff800068c6 ra : ffffffff800068c2 sp : ffffffff81803df0
gp : ffffffff81a1ab78 tp : ffffffff81814f80 t0 : ffffffffffffe000
t1 : 0000000000000001 t2 : 4c45203a76637369 s0 : ffffffff81803e40
s1 : 0000000000000004 a0 : 0000000000000000 a1 : ffffffffffffffff
a2 : 0000000000000004 a3 : 0000000000000000 a4 : 0000000000000001
a5 : 0000000000000000 a6 : 0000000000000000 a7 : 0000000052464e43
s2 : ffffffff80b4889c s3 : 000000000000082c s4 : ffffffff80b48828
s5 : 0000000000000828 s6 : ffffffff8131a0a0 s7 : 0000000000000fff
s8 : 0000000008000200 s9 : ffffffff8131a520 s10: 0000000000000018
s11: 000000000000000b t3 : 0000000000000001 t4 : 000000000000000d
t5 : ffffffffd8180000 t6 : ffffffff81803bc8
status: 0000000200000100 badaddr: 0000000000000000 cause: 0000000000000003
[<ffffffff800068c6>] patch_insn_write+0x222/0x2f6
[<ffffffff80006a36>] patch_text_nosync+0xc/0x2a
[<ffffffff80003b86>] riscv_cpufeature_patch_func+0x52/0x98
[<ffffffff80003348>] _apply_alternatives+0x46/0x86
[<ffffffff80c02d36>] apply_boot_alternatives+0x3c/0xfa
[<ffffffff80c03ad8>] setup_arch+0x584/0x5b8
[<ffffffff80c0075a>] start_kernel+0xa2/0x8f8
This issue was exposed by 702e64550b12 ("riscv: fpu: switch has_fpu() to
riscv_has_extension_likely()"), as it is the patching in has_fpu() that
triggers the splats in Guenter's report.
Take the text_mutex before doing any code patching to satisfy lockdep.
Fixes: ff689fd21cb1 ("riscv: add RISC-V Svpbmt extension support")
Fixes: a35707c3d850 ("riscv: add memory-type errata for T-Head")
Fixes: 1a0e5dbd3723 ("riscv: sifive: Add SiFive alternative ports")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/all/20230212154333.GA3760469@roeck-us.net/
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Samuel Holland <samuel@sholland.org>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20230212194735.491785-1-conor@kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
| -rw-r--r-- | arch/riscv/errata/sifive/errata.c | 3 | ||||
| -rw-r--r-- | arch/riscv/errata/thead/errata.c | 8 | ||||
| -rw-r--r-- | arch/riscv/kernel/cpufeature.c | 4 |
3 files changed, 13 insertions, 2 deletions
diff --git a/arch/riscv/errata/sifive/errata.c b/arch/riscv/errata/sifive/errata.c index ef9a4eec0dba..da55cb247e89 100644 --- a/arch/riscv/errata/sifive/errata.c +++ b/arch/riscv/errata/sifive/errata.c @@ -4,6 +4,7 @@ */ #include <linux/kernel.h> +#include <linux/memory.h> #include <linux/module.h> #include <linux/string.h> #include <linux/bug.h> @@ -107,8 +108,10 @@ void __init_or_module sifive_errata_patch_func(struct alt_entry *begin, tmp = (1U << alt->errata_id); if (cpu_req_errata & tmp) { + mutex_lock(&text_mutex); patch_text_nosync(ALT_OLD_PTR(alt), ALT_ALT_PTR(alt), alt->alt_len); + mutex_lock(&text_mutex); cpu_apply_errata |= tmp; } } diff --git a/arch/riscv/errata/thead/errata.c b/arch/riscv/errata/thead/errata.c index 1dd90a5f86f0..3b96a06d3c54 100644 --- a/arch/riscv/errata/thead/errata.c +++ b/arch/riscv/errata/thead/errata.c @@ -5,6 +5,7 @@ #include <linux/bug.h> #include <linux/kernel.h> +#include <linux/memory.h> #include <linux/module.h> #include <linux/string.h> #include <linux/uaccess.h> @@ -101,10 +102,13 @@ void __init_or_module thead_errata_patch_func(struct alt_entry *begin, struct al altptr = ALT_ALT_PTR(alt); /* On vm-alternatives, the mmu isn't running yet */ - if (stage == RISCV_ALTERNATIVES_EARLY_BOOT) + if (stage == RISCV_ALTERNATIVES_EARLY_BOOT) { memcpy(oldptr, altptr, alt->alt_len); - else + } else { + mutex_lock(&text_mutex); patch_text_nosync(oldptr, altptr, alt->alt_len); + mutex_unlock(&text_mutex); + } } } diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c index 21fb567e1b22..59d58ee0f68d 100644 --- a/arch/riscv/kernel/cpufeature.c +++ b/arch/riscv/kernel/cpufeature.c @@ -10,6 +10,7 @@ #include <linux/ctype.h> #include <linux/libfdt.h> #include <linux/log2.h> +#include <linux/memory.h> #include <linux/module.h> #include <linux/of.h> #include <asm/alternative.h> @@ -292,8 +293,11 @@ void __init_or_module riscv_cpufeature_patch_func(struct alt_entry *begin, oldptr = ALT_OLD_PTR(alt); altptr = ALT_ALT_PTR(alt); + + mutex_lock(&text_mutex); patch_text_nosync(oldptr, altptr, alt->alt_len); riscv_alternative_fix_offsets(oldptr, alt->alt_len, oldptr - altptr); + mutex_unlock(&text_mutex); } } #endif |