diff options
| author | Andy Lutomirski <luto@kernel.org> | 2015-07-23 15:37:48 -0700 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2018-06-16 22:21:34 +0100 |
| commit | 45dc1e88fb5a728c1f2186edafccf6581c9c99b8 (patch) | |
| tree | 08ce4b05d6e0d60cd240970592c605b6fe490c29 /arch | |
| parent | 82dd4b92ebcb628723cf47156263503beaa573a6 (diff) | |
| download | linux-stable-45dc1e88fb5a728c1f2186edafccf6581c9c99b8.tar.gz linux-stable-45dc1e88fb5a728c1f2186edafccf6581c9c99b8.tar.bz2 linux-stable-45dc1e88fb5a728c1f2186edafccf6581c9c99b8.zip | |
x86/entry/64: Don't use IST entry for #BP stack
commit d8ba61ba58c88d5207c1ba2f7d9a2280e7d03be9 upstream.
There's nothing IST-worthy about #BP/int3. We don't allow kprobes
in the small handful of places in the kernel that run at CPL0 with
an invalid stack, and 32-bit kernels have used normal interrupt
gates for #BP forever.
Furthermore, we don't allow kprobes in places that have usergs while
in kernel mode, so "paranoid" is also unnecessary.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[carnil: Backport to 3.16:
- Adjust finename change: arch/x86/kernel/entry_64.S
- Context changes
]
[bwh: Rebase on top of "x86/traps: Enable DEBUG_STACK after cpu_init() for
TRAP_DB/BP", and restore change in trap_init() instead of early_trap_init()]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/entry_64.S | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/traps.c | 16 |
2 files changed, 4 insertions, 14 deletions
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S index 3ae017f16930..1c4c26cfa778 100644 --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -1322,7 +1322,7 @@ apicinterrupt3 HYPERVISOR_CALLBACK_VECTOR \ #endif /* CONFIG_HYPERV */ idtentry debug do_debug has_error_code=0 paranoid=1 shift_ist=DEBUG_STACK -idtentry int3 do_int3 has_error_code=0 paranoid=1 shift_ist=DEBUG_STACK +idtentry int3 do_int3 has_error_code=0 idtentry stack_segment do_stack_segment has_error_code=1 #ifdef CONFIG_XEN idtentry xen_debug do_debug has_error_code=0 diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index b4ac2ca172eb..26ae4d7f8c45 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -334,7 +334,6 @@ exit: } NOKPROBE_SYMBOL(do_general_protection); -/* May run on IST stack. */ dotraplinkage void notrace do_int3(struct pt_regs *regs, long error_code) { enum ctx_state prev_state; @@ -367,15 +366,9 @@ dotraplinkage void notrace do_int3(struct pt_regs *regs, long error_code) SIGTRAP) == NOTIFY_STOP) goto exit; - /* - * Let others (NMI) know that the debug stack is in use - * as we may switch to the interrupt stack. - */ - debug_stack_usage_inc(); preempt_conditional_sti(regs); do_trap(X86_TRAP_BP, SIGTRAP, "int3", regs, error_code, NULL); preempt_conditional_cli(regs); - debug_stack_usage_dec(); exit: exception_exit(prev_state); } @@ -862,19 +855,16 @@ void __init trap_init(void) cpu_init(); /* - * X86_TRAP_DB and X86_TRAP_BP have been set - * in early_trap_init(). However, DEBUG_STACK works only after - * cpu_init() loads TSS. See comments in early_trap_init(). + * X86_TRAP_DB was installed in early_trap_init(). However, + * DEBUG_STACK works only after cpu_init() loads TSS. See comments + * in early_trap_init(). */ set_intr_gate_ist(X86_TRAP_DB, &debug, DEBUG_STACK); - /* int3 can be called from all */ - set_system_intr_gate_ist(X86_TRAP_BP, &int3, DEBUG_STACK); x86_init.irqs.trap_init(); #ifdef CONFIG_X86_64 memcpy(&debug_idt_table, &idt_table, IDT_ENTRIES * 16); set_nmi_gate(X86_TRAP_DB, &debug); - set_nmi_gate(X86_TRAP_BP, &int3); #endif } |