Commit ad82a928 authored Jun 18, 2018 by Vasily Gorbik Committed by Martin Schwidefsky Jul 02, 2018

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>

parent f6ea4d25

arch/s390/kernel/perf_regs.c

+2 −4

Original line number	Diff line number	Diff line
		@@ -12,9 +12,6 @@ u64 perf_reg_value(struct pt_regs *regs, int idx)
		{
		freg_t fp;

		if (WARN_ON_ONCE((u32)idx >= PERF_REG_S390_MAX))
		return 0;

		if (idx >= PERF_REG_S390_R0 && idx <= PERF_REG_S390_R15)
		return regs->gprs[idx];

		@@ -33,7 +30,8 @@ u64 perf_reg_value(struct pt_regs *regs, int idx)
		if (idx == PERF_REG_S390_PC)
		return regs->psw.addr;

		return regs->gprs[idx];
		WARN_ON_ONCE((u32)idx >= PERF_REG_S390_MAX);
		return 0;
		}

		#define REG_RESERVED (~((1UL << PERF_REG_S390_MAX) - 1))