Commit c46f59e9 authored Apr 11, 2017 by James Cowgill Committed by Ralf Baechle Apr 12, 2017

MIPS: Avoid BUG warning in arch_check_elf



arch_check_elf contains a usage of current_cpu_data that will call
smp_processor_id() with preemption enabled and therefore triggers a
"BUG: using smp_processor_id() in preemptible" warning when an fpxx
executable is loaded.

As a follow-up to commit b244614a ("MIPS: Avoid a BUG warning during
prctl(PR_SET_FP_MODE, ...)"), apply the same fix to arch_check_elf by
using raw_current_cpu_data instead. The rationale quoted from the previous
commit:

"It is assumed throughout the kernel that if any CPU has an FPU, then
all CPUs would have an FPU as well, so it is safe to perform the check
with preemption enabled - change the code to use raw_ variant of the
check to avoid the warning."

Fixes: 46490b57 ("MIPS: kernel: elf: Improve the overall ABI and FPU mode checks")
Signed-off-by: James Cowgill <James.Cowgill@imgtec.com>
CC: <stable@vger.kernel.org> # 4.0+
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/15951/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

parent e0211327

arch/mips/kernel/elf.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -257,7 +257,7 @@ int arch_check_elf(void _ehdr, bool has_interpreter, void _interp_ehdr,
		else if ((prog_req.fr1 && prog_req.frdefault) \|\|
		(prog_req.single && !prog_req.frdefault))
		/* Make sure 64-bit MIPS III/IV/64R1 will not pick FR1 */
		state->overall_fp_mode = ((current_cpu_data.fpu_id & MIPS_FPIR_F64) &&
		state->overall_fp_mode = ((raw_current_cpu_data.fpu_id & MIPS_FPIR_F64) &&
		cpu_has_mips_r2_r6) ?
		FP_FR1 : FP_FR0;
		else if (prog_req.fr1)

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