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linux-next/arch/s390/kernel/perf_regs.c
Vasily Gorbik ad82a928eb s390/perf: fix gcc 8 array-bounds warning
arch/s390/kernel/perf_regs.c:36:19: warning: array subscript 16 is above
array bounds of 'long unsigned int[16]' [-Warray-bounds]
  return regs->gprs[idx];

gcc tries to be smart here and since there is a condition:
if (idx >= PERF_REG_S390_R0 && idx <= PERF_REG_S390_R15)
	return regs->gprs[idx];
which covers all possible array subscripts, it gives the warning
for the last function return statement:
	return regs->gprs[idx];
which in presence of that condition does not really make sense and
should be replaced with "return 0;"

Also move WARN_ON_ONCE((u32)idx >= PERF_REG_S390_MAX) to the end of the
function.

Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-07-02 11:24:54 +02:00

70 lines
1.6 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include <linux/perf_event.h>
#include <linux/perf_regs.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/bug.h>
#include <asm/ptrace.h>
#include <asm/fpu/api.h>
#include <asm/fpu/types.h>
u64 perf_reg_value(struct pt_regs *regs, int idx)
{
freg_t fp;
if (idx >= PERF_REG_S390_R0 && idx <= PERF_REG_S390_R15)
return regs->gprs[idx];
if (idx >= PERF_REG_S390_FP0 && idx <= PERF_REG_S390_FP15) {
if (!user_mode(regs))
return 0;
idx -= PERF_REG_S390_FP0;
fp = MACHINE_HAS_VX ? *(freg_t *)(current->thread.fpu.vxrs + idx)
: current->thread.fpu.fprs[idx];
return fp.ui;
}
if (idx == PERF_REG_S390_MASK)
return regs->psw.mask;
if (idx == PERF_REG_S390_PC)
return regs->psw.addr;
WARN_ON_ONCE((u32)idx >= PERF_REG_S390_MAX);
return 0;
}
#define REG_RESERVED (~((1UL << PERF_REG_S390_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 (test_tsk_thread_flag(task, TIF_31BIT))
return PERF_SAMPLE_REGS_ABI_32;
return PERF_SAMPLE_REGS_ABI_64;
}
void perf_get_regs_user(struct perf_regs *regs_user,
struct pt_regs *regs,
struct pt_regs *regs_user_copy)
{
/*
* Use the regs from the first interruption and let
* perf_sample_regs_intr() handle interrupts (regs == get_irq_regs()).
*
* Also save FPU registers for user-space tasks only.
*/
regs_user->regs = task_pt_regs(current);
if (user_mode(regs_user->regs))
save_fpu_regs();
regs_user->abi = perf_reg_abi(current);
}