Re: [PATCH v2 2/3] arm64: fpsimd: Fix bad si_code for undiagnosed SIGFPE
From: Will Deacon <hidden>
Date: 2018-03-08 17:11:53
Also in:
linux-arch, linux-arm-kernel
On Thu, Mar 01, 2018 at 05:44:07PM +0000, Dave Martin wrote:
Currently a SIGFPE delivered in response to a floating-point exception trap may have si_code set to 0 on arm64. As reported by Eric, this is a bad idea since this is the value of SI_USER -- yet this signal is definitely not the result of kill(2), tgkill(2) etc. and si_uid and si_pid make limited sense whereas we do want to yield a value for si_addr (which doesn't exist for SI_USER).
[...]
quoted hunk ↗ jump to hunk
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index e7226c4..9040038 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c@@ -39,6 +39,7 @@ #include <linux/slab.h> #include <linux/sysctl.h> +#include <asm/esr.h> #include <asm/fpsimd.h> #include <asm/cputype.h> #include <asm/simd.h>@@ -867,18 +868,20 @@ asmlinkage void do_fpsimd_acc(unsigned int esr, struct pt_regs *regs) asmlinkage void do_fpsimd_exc(unsigned int esr, struct pt_regs *regs) { siginfo_t info; - unsigned int si_code = FPE_FIXME; - - if (esr & FPEXC_IOF) - si_code = FPE_FLTINV; - else if (esr & FPEXC_DZF) - si_code = FPE_FLTDIV; - else if (esr & FPEXC_OFF) - si_code = FPE_FLTOVF; - else if (esr & FPEXC_UFF) - si_code = FPE_FLTUND; - else if (esr & FPEXC_IXF) - si_code = FPE_FLTRES; + unsigned int si_code = FPE_FLTUNK;
Happy to take this patch once the dependency on FPE_FLTUNK in core code is resolved. Will