[tip: x86/entry] x86/entry: Convert General protection exception to IDTENTRY

From: tip-bot2 for Thomas Gleixner
Date: Tue May 19 2020 - 15:58:55 EST

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The following commit has been merged into the x86/entry branch of tip:

Commit-ID: d4271b8fccc0ebe87abe9a393ebfec972f5f6cb0
Gitweb: https://git.kernel.org/tip/d4271b8fccc0ebe87abe9a393ebfec972f5f6cb0
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Tue, 25 Feb 2020 23:16:25 +01:00
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Tue, 19 May 2020 16:04:02 +02:00

x86/entry: Convert General protection exception to IDTENTRY

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 prototypes
- Remove the RCU warning as the new entry macro ensures correctness

No functional change.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Alexandre Chartre <alexandre.chartre@xxxxxxxxxx>
Acked-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Acked-by: Andy Lutomirski <luto@xxxxxxxxxx>
Link: https://lkml.kernel.org/r/20200505134905.637269946@xxxxxxxxxxxxx

---
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 | 8 +++-----
arch/x86/xen/enlighten_pv.c | 2 +-
arch/x86/xen/xen-asm_64.S | 2 +-
8 files changed, 9 insertions(+), 20 deletions(-)

diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index ffe43d2..9d94a03 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -1302,7 +1302,7 @@ SYM_CODE_START(simd_coprocessor_error)
pushl $0
#ifdef CONFIG_X86_INVD_BUG
/* 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
@@ -1690,12 +1690,6 @@ SYM_CODE_START(int3)
jmp common_exception
SYM_CODE_END(int3)

-SYM_CODE_START(general_protection)
- ASM_CLAC
- pushl $do_general_protection
- jmp common_exception
-SYM_CODE_END(general_protection)
-
.pushsection .text, "ax"
SYM_CODE_START(rewind_stack_do_exit)
/* Prevent any naive code from trying to unwind to our caller. */
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index c92592d..5cecdd1 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1073,7 +1073,6 @@ apicinterrupt IRQ_WORK_VECTOR irq_work_interrupt smp_irq_work_interrupt
*/

idtentry X86_TRAP_BP int3 do_int3 has_error_code=0
-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
@@ -1209,7 +1208,7 @@ 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
diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index 4c0abd3..986fc65 100644
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -134,5 +134,6 @@ DECLARE_IDTENTRY(X86_TRAP_OLD_MF, exc_coproc_segment_overrun);
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
diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h
index 5e580ff..3a096a4 100644
--- a/arch/x86/include/asm/traps.h
+++ b/arch/x86/include/asm/traps.h
@@ -17,7 +17,6 @@ asmlinkage void int3(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);
@@ -33,7 +32,6 @@ asmlinkage void xen_xennmi(void);
asmlinkage void xen_xendebug(void);
asmlinkage void xen_int3(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);
@@ -48,7 +46,6 @@ dotraplinkage void do_debug(struct pt_regs *regs, long error_code);
dotraplinkage void do_nmi(struct pt_regs *regs, long error_code);
dotraplinkage void do_int3(struct pt_regs *regs, long error_code);
dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code, unsigned long cr2);
-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);
diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c
index 8d95cbf..6f0af12 100644
--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -82,7 +82,7 @@ static const __initconst struct idt_data def_idts[] = {
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),
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 3dfdc4d..e65c761 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -145,7 +145,7 @@ do_trap_no_signal(struct task_struct *tsk, int trapnr, const char *str,
* 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;
@@ -375,7 +375,7 @@ dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code, unsign
* 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;
@@ -494,7 +494,7 @@ static enum kernel_gp_hint get_kernel_gp_address(struct pt_regs *regs,

#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;
@@ -502,7 +502,6 @@ dotraplinkage void do_general_protection(struct pt_regs *regs, long error_code)
unsigned long gp_addr;
int ret;

- RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
cond_local_irq_enable(regs);

if (static_cpu_has(X86_FEATURE_UMIP)) {
@@ -570,7 +569,6 @@ dotraplinkage void do_general_protection(struct pt_regs *regs, long error_code)
exit:
cond_local_irq_disable(regs);
}
-NOKPROBE_SYMBOL(do_general_protection);

dotraplinkage void notrace do_int3(struct pt_regs *regs, long error_code)
{
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 333222a..9e648e0 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -631,7 +631,7 @@ static struct trap_array_entry trap_array[] = {
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 },
diff --git a/arch/x86/xen/xen-asm_64.S b/arch/x86/xen/xen-asm_64.S
index 0ecc055..802ec00 100644
--- 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_overrun
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

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