linux/arch/arm64/kernel/perf_regs.c
Will Deacon 5b75a6af11 arm64: perf: don't rely on layout of pt_regs when grabbing sp or pc
The current perf_regs code relies on sp and pc sitting just off the end
of the pt_regs->regs array. This is ugly and fragile, so this patch
checks for these register explicitly and returns the appropriate field.

Acked-by: Jean Pihet <jean.pihet@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2014-08-28 20:01:50 +01:00

53 lines
1.0 KiB
C

#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/perf_event.h>
#include <linux/bug.h>
#include <asm/compat.h>
#include <asm/perf_regs.h>
#include <asm/ptrace.h>
u64 perf_reg_value(struct pt_regs *regs, int idx)
{
if (WARN_ON_ONCE((u32)idx >= PERF_REG_ARM64_MAX))
return 0;
/*
* Compat (i.e. 32 bit) mode:
* - PC has been set in the pt_regs struct in kernel_entry,
* - Handle SP and LR here.
*/
if (compat_user_mode(regs)) {
if ((u32)idx == PERF_REG_ARM64_SP)
return regs->compat_sp;
if ((u32)idx == PERF_REG_ARM64_LR)
return regs->compat_lr;
}
if ((u32)idx == PERF_REG_ARM64_SP)
return regs->sp;
if ((u32)idx == PERF_REG_ARM64_PC)
return regs->pc;
return regs->regs[idx];
}
#define REG_RESERVED (~((1ULL << PERF_REG_ARM64_MAX) - 1))
int perf_reg_validate(u64 mask)
{
if (!mask || mask & REG_RESERVED)
return -EINVAL;
return 0;
}
u64 perf_reg_abi(struct task_struct *task)
{
if (is_compat_thread(task_thread_info(task)))
return PERF_SAMPLE_REGS_ABI_32;
else
return PERF_SAMPLE_REGS_ABI_64;
}