[patch V4 part 3 28/29] x86/entry: Convert SIMD coprocessor error exception to IDTENTRY

Thomas Gleixner
2020-05-05T14:15:50Z

From: Thomas Gleixner <tglx@linutronix.de>

Convert #XF to IDTENTRY_ERRORCODE:
- Implement the C entry point with DEFINE_IDTENTRY
- Emit the ASM stub with DECLARE_IDTENTRY
- Handle INVD_BUG in C
- Remove the ASM idtentry in 64bit
- Remove the open coded ASM entry code in 32bit
- Fixup the XEN/PV code
- Remove the old prototyoes
- Remove the RCU warning as the new entry macro ensures correctness

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
V3: Move the INVD bug handling to C (Brian)
---
arch/x86/entry/entry_32.S | 14 --------------
arch/x86/entry/entry_64.S | 1 -
arch/x86/include/asm/idtentry.h | 1 +
arch/x86/include/asm/traps.h | 3 ---
arch/x86/kernel/idt.c | 2 +-
arch/x86/kernel/traps.c | 29 +++++++++++++++++------------
arch/x86/xen/enlighten_pv.c | 2 +-
arch/x86/xen/xen-asm_64.S | 2 +-
8 files changed, 21 insertions(+), 33 deletions(-)

--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -1290,20 +1290,6 @@ SYM_FUNC_END(name)
/* The include is where all of the SMP etc. interrupts come from */
#include <asm/entry_arch.h>

-SYM_CODE_START(simd_coprocessor_error)
- ASM_CLAC
- pushl $0
-#ifdef CONFIG_X86_INVD_BUG
- /* AMD 486 bug: invd from userspace calls exception 19 instead of #GP */
- ALTERNATIVE "pushl $exc_general_protection", \
- "pushl $do_simd_coprocessor_error", \
- X86_FEATURE_XMM
-#else
- pushl $do_simd_coprocessor_error
-#endif
- jmp common_exception
-SYM_CODE_END(simd_coprocessor_error)
-
#ifdef CONFIG_PARAVIRT
SYM_CODE_START(native_iret)
iret
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1074,7 +1074,6 @@ apicinterrupt IRQ_WORK_VECTOR irq_work
*/

idtentry X86_TRAP_BP int3 do_int3 has_error_code=0
-idtentry X86_TRAP_XF simd_coprocessor_error do_simd_coprocessor_error has_error_code=0

idtentry X86_TRAP_PF page_fault do_page_fault has_error_code=1

--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -131,6 +131,7 @@ DECLARE_IDTENTRY(X86_TRAP_NM, exc_devic
DECLARE_IDTENTRY(X86_TRAP_OLD_MF, exc_coproc_segment_overrun);
DECLARE_IDTENTRY(X86_TRAP_SPURIOUS, exc_spurious_interrupt_bug);
DECLARE_IDTENTRY(X86_TRAP_MF, exc_coprocessor_error);
+DECLARE_IDTENTRY(X86_TRAP_XF, exc_simd_coprocessor_error);

/* Simple exception entries with error code pushed by hardware */
DECLARE_IDTENTRY_ERRORCODE(X86_TRAP_TS, exc_invalid_tss);
--- a/arch/x86/include/asm/traps.h
+++ b/arch/x86/include/asm/traps.h
@@ -22,7 +22,6 @@ asmlinkage void async_page_fault(void);
#ifdef CONFIG_X86_MCE
asmlinkage void machine_check(void);
#endif /* CONFIG_X86_MCE */
-asmlinkage void simd_coprocessor_error(void);

#if defined(CONFIG_X86_64) && defined(CONFIG_XEN_PV)
asmlinkage void xen_xennmi(void);
@@ -33,7 +32,6 @@ asmlinkage void xen_page_fault(void);
#ifdef CONFIG_X86_MCE
asmlinkage void xen_machine_check(void);
#endif /* CONFIG_X86_MCE */
-asmlinkage void xen_simd_coprocessor_error(void);
#endif

dotraplinkage void do_debug(struct pt_regs *regs, long error_code);
@@ -43,7 +41,6 @@ dotraplinkage void do_int3(struct pt_reg
dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code, unsigned long cr2);
#endif
dotraplinkage void do_page_fault(struct pt_regs *regs, unsigned long error_code, unsigned long address);
-dotraplinkage void do_simd_coprocessor_error(struct pt_regs *regs, long error_code);
#ifdef CONFIG_X86_32
dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code);
#endif
--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -83,7 +83,7 @@ static const __initconst struct idt_data
INTG(X86_TRAP_SPURIOUS, asm_exc_spurious_interrupt_bug),
INTG(X86_TRAP_MF, asm_exc_coprocessor_error),
INTG(X86_TRAP_AC, asm_exc_alignment_check),
- INTG(X86_TRAP_XF, simd_coprocessor_error),
+ INTG(X86_TRAP_XF, asm_exc_simd_coprocessor_error),

#ifdef CONFIG_X86_32
TSKG(X86_TRAP_DF, GDT_ENTRY_DOUBLEFAULT_TSS),
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -802,7 +802,7 @@ NOKPROBE_SYMBOL(do_debug);
* the correct behaviour even in the presence of the asynchronous
* IRQ13 behaviour
*/
-static void math_error(struct pt_regs *regs, int error_code, int trapnr)
+static void math_error(struct pt_regs *regs, int trapnr)
{
struct task_struct *task = current;
struct fpu *fpu = &task->thread.fpu;
@@ -813,15 +813,15 @@ static void math_error(struct pt_regs *r
cond_local_irq_enable(regs);

if (!user_mode(regs)) {
- if (fixup_exception(regs, trapnr, error_code, 0))
+ if (fixup_exception(regs, trapnr, 0, 0))
goto exit;

- task->thread.error_code = error_code;
+ task->thread.error_code = 0;
task->thread.trap_nr = trapnr;

- if (notify_die(DIE_TRAP, str, regs, error_code,
- trapnr, SIGFPE) != NOTIFY_STOP)
- die(str, regs, error_code);
+ if (notify_die(DIE_TRAP, str, regs, 0, trapnr,
+ SIGFPE) != NOTIFY_STOP)
+ die(str, regs, 0);
goto exit;
}

@@ -831,7 +831,7 @@ static void math_error(struct pt_regs *r
fpu__save(fpu);

task->thread.trap_nr = trapnr;
- task->thread.error_code = error_code;
+ task->thread.error_code = 0;

si_code = fpu__exception_code(fpu, trapnr);
/* Retry when we get spurious exceptions: */
@@ -846,14 +846,19 @@ static void math_error(struct pt_regs *r

DEFINE_IDTENTRY(exc_coprocessor_error)
{
- math_error(regs, 0, X86_TRAP_MF);
+ math_error(regs, X86_TRAP_MF);
}

-dotraplinkage void
-do_simd_coprocessor_error(struct pt_regs *regs, long error_code)
+DEFINE_IDTENTRY(exc_simd_coprocessor_error)
{
- RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
- math_error(regs, error_code, X86_TRAP_XF);
+ if (IS_ENABLED(CONFIG_X86_INVD_BUG)) {
+ /* AMD 486 bug: INVD in CPL 0 raises #XF instead of #GP */
+ if (!static_cpu_has(X86_FEATURE_XMM)) {
+ __exc_general_protection(regs, 0);
+ return;
+ }
+ }
+ math_error(regs, X86_TRAP_XF);
}

DEFINE_IDTENTRY(exc_spurious_interrupt_bug)
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -635,7 +635,7 @@ static struct trap_array_entry trap_arra
TRAP_ENTRY(exc_spurious_interrupt_bug, false ),
TRAP_ENTRY(exc_coprocessor_error, false ),
TRAP_ENTRY(exc_alignment_check, false ),
- { simd_coprocessor_error, xen_simd_coprocessor_error, false },
+ TRAP_ENTRY(exc_simd_coprocessor_error, false ),
};

static bool __ref get_trap_addr(void **addr, unsigned int ist)
--- a/arch/x86/xen/xen-asm_64.S
+++ b/arch/x86/xen/xen-asm_64.S
@@ -50,7 +50,7 @@ xen_pv_trap asm_exc_alignment_check
#ifdef CONFIG_X86_MCE
xen_pv_trap machine_check
#endif /* CONFIG_X86_MCE */
-xen_pv_trap simd_coprocessor_error
+xen_pv_trap asm_exc_simd_coprocessor_error
#ifdef CONFIG_IA32_EMULATION
xen_pv_trap entry_INT80_compat
#endif