diff options
| author | Heiko Carstens <hca@linux.ibm.com> | 2021-10-06 11:59:29 +0200 |
|---|---|---|
| committer | Vasily Gorbik <gor@linux.ibm.com> | 2021-10-11 20:55:59 +0200 |
| commit | a30b5b03047602be56c5b8ffc3a0e4cfed17561c (patch) | |
| tree | 43460176f4fd420f8f9748519c355915ba9c986a /arch/s390 | |
| parent | 3990b5baf225a3a96e70a784747d31002686c300 (diff) | |
s390/ptrace: add function argument access API
Add regs_get_kernel_argument() which returns Nth argument of a
function call.
This enables ftrace kprobe events to access kernel function arguments
via $argN syntax.
This is the s390 variant of commit a823c35ff2ed ("arm64: ptrace: Add
function argument access API").
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Steffen Maier <maier@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diffstat (limited to 'arch/s390')
| -rw-r--r-- | arch/s390/Kconfig | 1 | ||||
| -rw-r--r-- | arch/s390/include/asm/ptrace.h | 19 |
2 files changed, 20 insertions, 0 deletions
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index 03eb3ec08b07..c35c98e515a2 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -160,6 +160,7 @@ config S390 select HAVE_FAST_GUP select HAVE_FENTRY select HAVE_FTRACE_MCOUNT_RECORD + select HAVE_FUNCTION_ARG_ACCESS_API select HAVE_FUNCTION_ERROR_INJECTION select HAVE_FUNCTION_GRAPH_TRACER select HAVE_FUNCTION_TRACER diff --git a/arch/s390/include/asm/ptrace.h b/arch/s390/include/asm/ptrace.h index 662ee212ba51..82fc11907451 100644 --- a/arch/s390/include/asm/ptrace.h +++ b/arch/s390/include/asm/ptrace.h @@ -196,6 +196,25 @@ const char *regs_query_register_name(unsigned int offset); unsigned long regs_get_register(struct pt_regs *regs, unsigned int offset); unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n); +/** + * regs_get_kernel_argument() - get Nth function argument in kernel + * @regs: pt_regs of that context + * @n: function argument number (start from 0) + * + * regs_get_kernel_argument() returns @n th argument of the function call. + */ +static inline unsigned long regs_get_kernel_argument(struct pt_regs *regs, + unsigned int n) +{ + unsigned int argoffset = STACK_FRAME_OVERHEAD / sizeof(long); + +#define NR_REG_ARGUMENTS 5 + if (n < NR_REG_ARGUMENTS) + return regs_get_register(regs, 2 + n); + n -= NR_REG_ARGUMENTS; + return regs_get_kernel_stack_nth(regs, argoffset + n); +} + static inline unsigned long kernel_stack_pointer(struct pt_regs *regs) { return regs->gprs[15]; |