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authorIngo Molnar <mingo@kernel.org>2015-04-30 09:29:38 +0200
committerIngo Molnar <mingo@kernel.org>2015-05-19 15:48:06 +0200
commite1cebad49c54e0241e101ebf63d5238fe1137749 (patch)
tree8896836c0c576ff4ea58ff11cb509b4e32498751 /arch/x86/kernel/traps.c
parentacd58a3ad0ed5875fb88bbb078309a3d7ee147a0 (diff)
downloadlinux-e1cebad49c54e0241e101ebf63d5238fe1137749.tar.bz2
x86/fpu: Factor out the exception error code handling code
Factor out the FPU error code handling code from traps.c and fpu/internal.h and move them close to each other. Also convert the helper functions to 'struct fpu *', which further simplifies them. Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/traps.c')
-rw-r--r--arch/x86/kernel/traps.c67
1 files changed, 12 insertions, 55 deletions
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 48dfcd9ed351..cab397d0085f 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -708,8 +708,8 @@ NOKPROBE_SYMBOL(do_debug);
static void math_error(struct pt_regs *regs, int error_code, int trapnr)
{
struct task_struct *task = current;
+ struct fpu *fpu = &task->thread.fpu;
siginfo_t info;
- unsigned short err;
char *str = (trapnr == X86_TRAP_MF) ? "fpu exception" :
"simd exception";
@@ -717,8 +717,7 @@ static void math_error(struct pt_regs *regs, int error_code, int trapnr)
return;
conditional_sti(regs);
- if (!user_mode(regs))
- {
+ if (!user_mode(regs)) {
if (!fixup_exception(regs)) {
task->thread.error_code = error_code;
task->thread.trap_nr = trapnr;
@@ -730,62 +729,20 @@ static void math_error(struct pt_regs *regs, int error_code, int trapnr)
/*
* Save the info for the exception handler and clear the error.
*/
- fpu__save(&task->thread.fpu);
- task->thread.trap_nr = trapnr;
+ fpu__save(fpu);
+
+ task->thread.trap_nr = trapnr;
task->thread.error_code = error_code;
- info.si_signo = SIGFPE;
- info.si_errno = 0;
- info.si_addr = (void __user *)uprobe_get_trap_addr(regs);
- if (trapnr == X86_TRAP_MF) {
- unsigned short cwd, swd;
- /*
- * (~cwd & swd) will mask out exceptions that are not set to unmasked
- * status. 0x3f is the exception bits in these regs, 0x200 is the
- * C1 reg you need in case of a stack fault, 0x040 is the stack
- * fault bit. We should only be taking one exception at a time,
- * so if this combination doesn't produce any single exception,
- * then we have a bad program that isn't synchronizing its FPU usage
- * and it will suffer the consequences since we won't be able to
- * fully reproduce the context of the exception
- */
- cwd = get_fpu_cwd(task);
- swd = get_fpu_swd(task);
+ info.si_signo = SIGFPE;
+ info.si_errno = 0;
+ info.si_addr = (void __user *)uprobe_get_trap_addr(regs);
- err = swd & ~cwd;
- } else {
- /*
- * The SIMD FPU exceptions are handled a little differently, as there
- * is only a single status/control register. Thus, to determine which
- * unmasked exception was caught we must mask the exception mask bits
- * at 0x1f80, and then use these to mask the exception bits at 0x3f.
- */
- unsigned short mxcsr = get_fpu_mxcsr(task);
- err = ~(mxcsr >> 7) & mxcsr;
- }
+ info.si_code = fpu__exception_code(fpu, trapnr);
- if (err & 0x001) { /* Invalid op */
- /*
- * swd & 0x240 == 0x040: Stack Underflow
- * swd & 0x240 == 0x240: Stack Overflow
- * User must clear the SF bit (0x40) if set
- */
- info.si_code = FPE_FLTINV;
- } else if (err & 0x004) { /* Divide by Zero */
- info.si_code = FPE_FLTDIV;
- } else if (err & 0x008) { /* Overflow */
- info.si_code = FPE_FLTOVF;
- } else if (err & 0x012) { /* Denormal, Underflow */
- info.si_code = FPE_FLTUND;
- } else if (err & 0x020) { /* Precision */
- info.si_code = FPE_FLTRES;
- } else {
- /*
- * If we're using IRQ 13, or supposedly even some trap
- * X86_TRAP_MF implementations, it's possible
- * we get a spurious trap, which is not an error.
- */
+ /* Retry when we get spurious exceptions: */
+ if (!info.si_code)
return;
- }
+
force_sig_info(SIGFPE, &info, task);
}