x86-32: Rework cache flush denied handler

The cache flush denied error is an erratum on some AMD 486 clones.  If an invd
instruction is executed in userspace, the processor calls exception 19 (13 hex)
instead of #GP (13 decimal).  On cpus where XMM is not supported, redirect
exception 19 to do_general_protection().  Also, remove die_if_kernel(), since
this was the last user.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
LKML-Reference: <1269176446-2489-2-git-send-email-brgerst@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 3 insertions, 28 deletions

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 1168e4454188..a16c9dfe6b70 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -108,15 +108,6 @@ static inline void preempt_conditional_cli(struct pt_regs *regs)
         dec_preempt_count();
 }
 
-#ifdef CONFIG_X86_32
-static inline void
-die_if_kernel(const char *str, struct pt_regs *regs, long err)
-{
-        if (!user_mode_vm(regs))
-                die(str, regs, err);
-}
-#endif
-
 static void __kprobes
 do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,
         long error_code, siginfo_t *info)
@@ -729,30 +720,14 @@ do_simd_coprocessor_error(struct pt_regs *regs, long error_code)
         conditional_sti(regs);
 
 #ifdef CONFIG_X86_32
-        if (cpu_has_xmm) {
-                /* Handle SIMD FPU exceptions on PIII+ processors. */
-                ignore_fpu_irq = 1;
-                simd_math_error((void __user *)regs->ip);
-                return;
-        }
-        /*
-         * Handle strange cache flush from user space exception
-         * in all other cases.  This is undocumented behaviour.
-         */
-        if (regs->flags & X86_VM_MASK) {
-                handle_vm86_fault((struct kernel_vm86_regs *)regs, error_code);
-                return;
-        }
-        current->thread.trap_no = 19;
-        current->thread.error_code = error_code;
-        die_if_kernel("cache flush denied", regs, error_code);
-        force_sig(SIGSEGV, current);
+        ignore_fpu_irq = 1;
 #else
         if (!user_mode(regs) &&
                         kernel_math_error(regs, "kernel simd math error", 19))
                 return;
-        simd_math_error((void __user *)regs->ip);
 #endif
+
+        simd_math_error((void __user *)regs->ip);
 }
 
 dotraplinkage void