From d77290507ab2ac691d50389e255ebd11a6cbc35a Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 25 Feb 2020 23:16:30 +0100 Subject: [PATCH] x86/entry/32: Convert IRET exception to IDTENTRY_SW Convert the IRET exception handler to IDTENTRY_SW. This is slightly different than the conversions of hardware exceptions as the IRET exception is invoked via an exception table when IRET faults. So it just uses the IDTENTRY_SW mechanism for consistency. It does not emit ASM code as it does not fit the other idtentry exceptions. - Implement the C entry point with DEFINE_IDTENTRY_SW() which maps to DEFINE_IDTENTRY() - 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 Reviewed-by: Alexandre Chartre Acked-by: Peter Zijlstra Acked-by: Andy Lutomirski Link: https://lkml.kernel.org/r/20200505134906.128769226@linutronix.de --- arch/x86/entry/entry_32.S | 14 +++++++------- arch/x86/include/asm/idtentry.h | 10 ++++++++++ arch/x86/include/asm/traps.h | 3 --- arch/x86/kernel/traps.c | 8 +++----- arch/x86/xen/xen-asm_32.S | 2 +- 5 files changed, 21 insertions(+), 16 deletions(-) diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index c93fb73af0398..f7a5f1cda058a 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -1147,9 +1147,9 @@ restore_all_kernel: jmp .Lirq_return .section .fixup, "ax" -SYM_CODE_START(iret_exc) +SYM_CODE_START(asm_iret_error) pushl $0 # no error code - pushl $do_iret_error + pushl $iret_error #ifdef CONFIG_DEBUG_ENTRY /* @@ -1163,10 +1163,10 @@ SYM_CODE_START(iret_exc) popl %eax #endif - jmp common_exception -SYM_CODE_END(iret_exc) + jmp handle_exception +SYM_CODE_END(asm_iret_error) .previous - _ASM_EXTABLE(.Lirq_return, iret_exc) + _ASM_EXTABLE(.Lirq_return, asm_iret_error) SYM_FUNC_END(entry_INT80_32) .macro FIXUP_ESPFIX_STACK @@ -1293,7 +1293,7 @@ SYM_FUNC_END(name) #ifdef CONFIG_PARAVIRT SYM_CODE_START(native_iret) iret - _ASM_EXTABLE(native_iret, iret_exc) + _ASM_EXTABLE(native_iret, asm_iret_error) SYM_CODE_END(native_iret) #endif @@ -1358,7 +1358,7 @@ SYM_FUNC_START(xen_failsafe_callback) popl %eax lea 16(%esp), %esp jz 5f - jmp iret_exc + jmp asm_iret_error 5: pushl $-1 /* orig_ax = -1 => not a system call */ SAVE_ALL ENCODE_FRAME_POINTER diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h index 99d4759bd9147..ee6ebfef7e57d 100644 --- a/arch/x86/include/asm/idtentry.h +++ b/arch/x86/include/asm/idtentry.h @@ -57,6 +57,10 @@ __visible noinstr void func(struct pt_regs *regs) \ \ static __always_inline void __##func(struct pt_regs *regs) +/* Special case for 32bit IRET 'trap' */ +#define DECLARE_IDTENTRY_SW DECLARE_IDTENTRY +#define DEFINE_IDTENTRY_SW DEFINE_IDTENTRY + /** * DECLARE_IDTENTRY_ERRORCODE - Declare functions for simple IDT entry points * Error code pushed by hardware @@ -111,6 +115,9 @@ static __always_inline void __##func(struct pt_regs *regs, \ #define DECLARE_IDTENTRY_ERRORCODE(vector, func) \ idtentry vector asm_##func func has_error_code=1 sane=1 +/* Special case for 32bit IRET 'trap'. Do not emit ASM code */ +#define DECLARE_IDTENTRY_SW(vector, func) + #endif /* __ASSEMBLY__ */ /* @@ -133,6 +140,9 @@ 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); +/* 32bit software IRET trap. Do not emit ASM code */ +DECLARE_IDTENTRY_SW(X86_TRAP_IRET, iret_error); + /* Simple exception entries with error code pushed by hardware */ DECLARE_IDTENTRY_ERRORCODE(X86_TRAP_TS, exc_invalid_tss); DECLARE_IDTENTRY_ERRORCODE(X86_TRAP_NP, exc_segment_not_present); diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h index e7eb7532233d3..5774d0b6cf77d 100644 --- a/arch/x86/include/asm/traps.h +++ b/arch/x86/include/asm/traps.h @@ -39,9 +39,6 @@ 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_page_fault(struct pt_regs *regs, unsigned long error_code, unsigned long address); -#ifdef CONFIG_X86_32 -dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code); -#endif dotraplinkage void do_mce(struct pt_regs *regs, long error_code); #ifdef CONFIG_X86_64 diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 1702922ebd9c1..b28a64d7691fb 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -925,14 +925,12 @@ DEFINE_IDTENTRY(exc_device_not_available) } #ifdef CONFIG_X86_32 -dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code) +DEFINE_IDTENTRY_SW(iret_error) { - RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU"); local_irq_enable(); - - if (notify_die(DIE_TRAP, "iret exception", regs, error_code, + if (notify_die(DIE_TRAP, "iret exception", regs, 0, X86_TRAP_IRET, SIGILL) != NOTIFY_STOP) { - do_trap(X86_TRAP_IRET, SIGILL, "iret exception", regs, error_code, + do_trap(X86_TRAP_IRET, SIGILL, "iret exception", regs, 0, ILL_BADSTK, (void __user *)NULL); } local_irq_disable(); diff --git a/arch/x86/xen/xen-asm_32.S b/arch/x86/xen/xen-asm_32.S index 2712e91553063..812ff01e4e341 100644 --- a/arch/x86/xen/xen-asm_32.S +++ b/arch/x86/xen/xen-asm_32.S @@ -117,7 +117,7 @@ iret_restore_end: 1: iret xen_iret_end_crit: - _ASM_EXTABLE(1b, iret_exc) + _ASM_EXTABLE(1b, asm_iret_error) hyper_iret: /* put this out of line since its very rarely used */ -- 2.30.2