Commit e17f8234 authored by Boris Ostrovsky's avatar Boris Ostrovsky Committed by Ingo Molnar

x86/entry/64/paravirt: Use paravirt-safe macro to access eflags

Commit 1d3e53e8 ("x86/entry/64: Refactor IRQ stacks and make them
NMI-safe") added DEBUG_ENTRY_ASSERT_IRQS_OFF macro that acceses eflags
using 'pushfq' instruction when testing for IF bit. On PV Xen guests
looking at IF flag directly will always see it set, resulting in 'ud2'.

Introduce SAVE_FLAGS() macro that will use appropriate save_fl pv op when
running paravirt.
Signed-off-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarJuergen Gross <jgross@suse.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
Cc: xen-devel@lists.xenproject.org
Link: https://lkml.kernel.org/r/20171204150604.899457242@linutronix.deSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 2aeb0736
...@@ -462,12 +462,13 @@ END(irq_entries_start) ...@@ -462,12 +462,13 @@ END(irq_entries_start)
.macro DEBUG_ENTRY_ASSERT_IRQS_OFF .macro DEBUG_ENTRY_ASSERT_IRQS_OFF
#ifdef CONFIG_DEBUG_ENTRY #ifdef CONFIG_DEBUG_ENTRY
pushfq pushq %rax
testl $X86_EFLAGS_IF, (%rsp) SAVE_FLAGS(CLBR_RAX)
testl $X86_EFLAGS_IF, %eax
jz .Lokay_\@ jz .Lokay_\@
ud2 ud2
.Lokay_\@: .Lokay_\@:
addq $8, %rsp popq %rax
#endif #endif
.endm .endm
......
...@@ -142,6 +142,9 @@ static inline notrace unsigned long arch_local_irq_save(void) ...@@ -142,6 +142,9 @@ static inline notrace unsigned long arch_local_irq_save(void)
swapgs; \ swapgs; \
sysretl sysretl
#ifdef CONFIG_DEBUG_ENTRY
#define SAVE_FLAGS(x) pushfq; popq %rax
#endif
#else #else
#define INTERRUPT_RETURN iret #define INTERRUPT_RETURN iret
#define ENABLE_INTERRUPTS_SYSEXIT sti; sysexit #define ENABLE_INTERRUPTS_SYSEXIT sti; sysexit
......
...@@ -927,6 +927,15 @@ extern void default_banner(void); ...@@ -927,6 +927,15 @@ extern void default_banner(void);
PARA_SITE(PARA_PATCH(pv_cpu_ops, PV_CPU_usergs_sysret64), \ PARA_SITE(PARA_PATCH(pv_cpu_ops, PV_CPU_usergs_sysret64), \
CLBR_NONE, \ CLBR_NONE, \
jmp PARA_INDIRECT(pv_cpu_ops+PV_CPU_usergs_sysret64)) jmp PARA_INDIRECT(pv_cpu_ops+PV_CPU_usergs_sysret64))
#ifdef CONFIG_DEBUG_ENTRY
#define SAVE_FLAGS(clobbers) \
PARA_SITE(PARA_PATCH(pv_irq_ops, PV_IRQ_save_fl), clobbers, \
PV_SAVE_REGS(clobbers | CLBR_CALLEE_SAVE); \
call PARA_INDIRECT(pv_irq_ops+PV_IRQ_save_fl); \
PV_RESTORE_REGS(clobbers | CLBR_CALLEE_SAVE);)
#endif
#endif /* CONFIG_X86_32 */ #endif /* CONFIG_X86_32 */
#endif /* __ASSEMBLY__ */ #endif /* __ASSEMBLY__ */
......
...@@ -23,6 +23,9 @@ int main(void) ...@@ -23,6 +23,9 @@ int main(void)
#ifdef CONFIG_PARAVIRT #ifdef CONFIG_PARAVIRT
OFFSET(PV_CPU_usergs_sysret64, pv_cpu_ops, usergs_sysret64); OFFSET(PV_CPU_usergs_sysret64, pv_cpu_ops, usergs_sysret64);
OFFSET(PV_CPU_swapgs, pv_cpu_ops, swapgs); OFFSET(PV_CPU_swapgs, pv_cpu_ops, swapgs);
#ifdef CONFIG_DEBUG_ENTRY
OFFSET(PV_IRQ_save_fl, pv_irq_ops, save_fl);
#endif
BLANK(); BLANK();
#endif #endif
......
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