[patch 19/24] x86/entry: Convert General protection exception to IDTENTRY

Thomas Gleixner
2020-02-25T23:28:31Z

Convert #GP to IDTENTRY_ERRORCODE:
- Implement the C entry point with DEFINE_IDTENTRY
- Emit the ASM stub with DECLARE_IDTENTRY
- Remove the ASM idtentry in 64bit
- Remove the open coded ASM entry code in 32bit
- Fixup the XEN/PV code
- Remove the old prototyoes

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/entry/entry_32.S | 8 +-------
arch/x86/entry/entry_64.S | 3 +--
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 | 7 +++----
arch/x86/xen/enlighten_pv.c | 2 +-
arch/x86/xen/xen-asm_64.S | 2 +-
8 files changed, 9 insertions(+), 19 deletions(-)

--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -732,7 +732,7 @@
.macro idtentry_push_func vector cfunc
.if \vector == X86_TRAP_XF
/* AMD 486 bug: invd from userspace calls exception 19 instead of #GP */
- ALTERNATIVE "pushl $do_general_protection", \
+ ALTERNATIVE "pushl $exc_general_protection", \
"pushl $do_simd_coprocessor_error", \
X86_FEATURE_XMM
.else
@@ -1652,12 +1652,6 @@ SYM_CODE_START(nmi)
#endif
SYM_CODE_END(nmi)

-SYM_CODE_START(general_protection)
- ASM_CLAC
- pushl $do_general_protection
- jmp common_exception
-SYM_CODE_END(general_protection)
-
#ifdef CONFIG_KVM_GUEST
SYM_CODE_START(async_page_fault)
ASM_CLAC
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1061,7 +1061,6 @@ apicinterrupt IRQ_WORK_VECTOR irq_work
* Exception entry points.
*/

-idtentry X86_TRAP_GP general_protection do_general_protection has_error_code=1
idtentry X86_TRAP_SPURIOUS spurious_interrupt_bug do_spurious_interrupt_bug has_error_code=0
idtentry X86_TRAP_MF coprocessor_error do_coprocessor_error has_error_code=0
idtentry X86_TRAP_AC alignment_check do_alignment_check has_error_code=1
@@ -1201,7 +1200,7 @@ SYM_CODE_START(xen_failsafe_callback)
addq $0x30, %rsp
pushq $0 /* RIP */
UNWIND_HINT_IRET_REGS offset=8
- jmp general_protection
+ jmp asm_exc_general_protection
1: /* Segment mismatch => Category 1 (Bad segment). Retry the IRET. */
movq (%rsp), %rcx
movq 8(%rsp), %r11
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -132,5 +132,6 @@ DECLARE_IDTENTRY(X86_TRAP_OLD_MF, exc_co
DECLARE_IDTENTRY_ERRORCODE(X86_TRAP_TS, exc_invalid_tss);
DECLARE_IDTENTRY_ERRORCODE(X86_TRAP_NP, exc_segment_not_present);
DECLARE_IDTENTRY_ERRORCODE(X86_TRAP_SS, exc_stack_segment);
+DECLARE_IDTENTRY_ERRORCODE(X86_TRAP_GP, exc_general_protection);

#endif
--- a/arch/x86/include/asm/traps.h
+++ b/arch/x86/include/asm/traps.h
@@ -16,7 +16,6 @@ asmlinkage void nmi(void);
#ifdef CONFIG_X86_64
asmlinkage void double_fault(void);
#endif
-asmlinkage void general_protection(void);
asmlinkage void page_fault(void);
asmlinkage void async_page_fault(void);
asmlinkage void spurious_interrupt_bug(void);
@@ -31,7 +30,6 @@ asmlinkage void simd_coprocessor_error(v
asmlinkage void xen_xennmi(void);
asmlinkage void xen_xendebug(void);
asmlinkage void xen_double_fault(void);
-asmlinkage void xen_general_protection(void);
asmlinkage void xen_page_fault(void);
asmlinkage void xen_spurious_interrupt_bug(void);
asmlinkage void xen_coprocessor_error(void);
@@ -47,7 +45,6 @@ dotraplinkage void do_nmi(struct pt_regs
#if defined(CONFIG_X86_64) || defined(CONFIG_DOUBLEFAULT)
dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code, unsigned long cr2);
#endif
-dotraplinkage void do_general_protection(struct pt_regs *regs, long error_code);
dotraplinkage void do_page_fault(struct pt_regs *regs, unsigned long error_code, unsigned long address);
dotraplinkage void do_spurious_interrupt_bug(struct pt_regs *regs, long error_code);
dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code);
--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -79,7 +79,7 @@ static const __initconst struct idt_data
INTG(X86_TRAP_TS, asm_exc_invalid_tss),
INTG(X86_TRAP_NP, asm_exc_segment_not_present),
INTG(X86_TRAP_SS, asm_exc_stack_segment),
- INTG(X86_TRAP_GP, general_protection),
+ INTG(X86_TRAP_GP, asm_exc_general_protection),
INTG(X86_TRAP_SPURIOUS, spurious_interrupt_bug),
INTG(X86_TRAP_MF, coprocessor_error),
INTG(X86_TRAP_AC, alignment_check),
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -214,7 +214,7 @@ do_trap_no_signal(struct task_struct *ts
* process no chance to handle the signal and notice the
* kernel fault information, so that won't result in polluting
* the information about previously queued, but not yet
- * delivered, faults. See also do_general_protection below.
+ * delivered, faults. See also exc_general_protection below.
*/
tsk->thread.error_code = error_code;
tsk->thread.trap_nr = trapnr;
@@ -410,7 +410,7 @@ dotraplinkage void do_double_fault(struc
* which is what the stub expects, given that the faulting
* RIP will be the IRET instruction.
*/
- regs->ip = (unsigned long)general_protection;
+ regs->ip = (unsigned long)asm_exc_general_protection;
regs->sp = (unsigned long)&gpregs->orig_ax;

return;
@@ -529,7 +529,7 @@ static enum kernel_gp_hint get_kernel_gp

#define GPFSTR "general protection fault"

-dotraplinkage void do_general_protection(struct pt_regs *regs, long error_code)
+DEFINE_IDTENTRY_ERRORCODE(exc_general_protection)
{
char desc[sizeof(GPFSTR) + 50 + 2*sizeof(unsigned long) + 1] = GPFSTR;
enum kernel_gp_hint hint = GP_NO_HINT;
@@ -603,7 +603,6 @@ dotraplinkage void do_general_protection
die_addr(desc, regs, error_code, gp_addr);

}
-NOKPROBE_SYMBOL(do_general_protection);

DEFINE_IDTENTRY(exc_int3)
{
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -628,7 +628,7 @@ static struct trap_array_entry trap_arra
TRAP_ENTRY(exc_invalid_tss, false ),
TRAP_ENTRY(exc_segment_not_present, false ),
TRAP_ENTRY(exc_stack_segment, false ),
- { general_protection, xen_general_protection, false },
+ TRAP_ENTRY(exc_general_protection, false ),
{ spurious_interrupt_bug, xen_spurious_interrupt_bug, false },
{ coprocessor_error, xen_coprocessor_error, false },
{ alignment_check, xen_alignment_check, false },
--- a/arch/x86/xen/xen-asm_64.S
+++ b/arch/x86/xen/xen-asm_64.S
@@ -42,7 +42,7 @@ xen_pv_trap asm_exc_coproc_segment_overr
xen_pv_trap asm_exc_invalid_tss
xen_pv_trap asm_exc_segment_not_present
xen_pv_trap asm_exc_stack_segment
-xen_pv_trap general_protection
+xen_pv_trap asm_exc_general_protection
xen_pv_trap page_fault
xen_pv_trap spurious_interrupt_bug
xen_pv_trap coprocessor_error