diff options
author | Thomas Gleixner <tglx@linutronix.de> | 2020-07-23 00:00:01 +0200 |
---|---|---|
committer | Thomas Gleixner <tglx@linutronix.de> | 2020-07-24 15:04:58 +0200 |
commit | 0b085e68f4072024ecaa3889aeeaab5f6c8eba5c (patch) | |
tree | 665688bdb526ca7e2b17a0eebabc9b875eb7eb87 /arch/x86/entry | |
parent | 8d5ea35c5e9139dbd19a3d73985d008d36c9968f (diff) |
x86/entry: Consolidate 32/64 bit syscall entry
64bit and 32bit entry code have the same open coded syscall entry handling
after the bitwidth specific bits.
Move it to a helper function and share the code.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200722220520.051234096@linutronix.de
Diffstat (limited to 'arch/x86/entry')
-rw-r--r-- | arch/x86/entry/common.c | 93 |
1 files changed, 41 insertions, 52 deletions
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c index ab6cb8602c0b..68d5c86b1985 100644 --- a/arch/x86/entry/common.c +++ b/arch/x86/entry/common.c @@ -366,8 +366,7 @@ __visible noinstr void syscall_return_slowpath(struct pt_regs *regs) exit_to_user_mode(); } -#ifdef CONFIG_X86_64 -__visible noinstr void do_syscall_64(unsigned long nr, struct pt_regs *regs) +static noinstr long syscall_enter(struct pt_regs *regs, unsigned long nr) { struct thread_info *ti; @@ -379,6 +378,16 @@ __visible noinstr void do_syscall_64(unsigned long nr, struct pt_regs *regs) if (READ_ONCE(ti->flags) & _TIF_WORK_SYSCALL_ENTRY) nr = syscall_trace_enter(regs); + instrumentation_end(); + return nr; +} + +#ifdef CONFIG_X86_64 +__visible noinstr void do_syscall_64(unsigned long nr, struct pt_regs *regs) +{ + nr = syscall_enter(regs, nr); + + instrumentation_begin(); if (likely(nr < NR_syscalls)) { nr = array_index_nospec(nr, NR_syscalls); regs->ax = sys_call_table[nr](regs); @@ -390,64 +399,53 @@ __visible noinstr void do_syscall_64(unsigned long nr, struct pt_regs *regs) regs->ax = x32_sys_call_table[nr](regs); #endif } - __syscall_return_slowpath(regs); - instrumentation_end(); - exit_to_user_mode(); + syscall_return_slowpath(regs); } #endif #if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION) +static __always_inline unsigned int syscall_32_enter(struct pt_regs *regs) +{ + if (IS_ENABLED(CONFIG_IA32_EMULATION)) + current_thread_info()->status |= TS_COMPAT; + /* + * Subtlety here: if ptrace pokes something larger than 2^32-1 into + * orig_ax, the unsigned int return value truncates it. This may + * or may not be necessary, but it matches the old asm behavior. + */ + return syscall_enter(regs, (unsigned int)regs->orig_ax); +} + /* - * Does a 32-bit syscall. Called with IRQs on in CONTEXT_KERNEL. Does - * all entry and exit work and returns with IRQs off. This function is - * extremely hot in workloads that use it, and it's usually called from - * do_fast_syscall_32, so forcibly inline it to improve performance. + * Invoke a 32-bit syscall. Called with IRQs on in CONTEXT_KERNEL. */ -static void do_syscall_32_irqs_on(struct pt_regs *regs) +static __always_inline void do_syscall_32_irqs_on(struct pt_regs *regs, + unsigned int nr) { - struct thread_info *ti = current_thread_info(); - unsigned int nr = (unsigned int)regs->orig_ax; - -#ifdef CONFIG_IA32_EMULATION - ti->status |= TS_COMPAT; -#endif - - if (READ_ONCE(ti->flags) & _TIF_WORK_SYSCALL_ENTRY) { - /* - * Subtlety here: if ptrace pokes something larger than - * 2^32-1 into orig_ax, this truncates it. This may or - * may not be necessary, but it matches the old asm - * behavior. - */ - nr = syscall_trace_enter(regs); - } - if (likely(nr < IA32_NR_syscalls)) { + instrumentation_begin(); nr = array_index_nospec(nr, IA32_NR_syscalls); regs->ax = ia32_sys_call_table[nr](regs); + instrumentation_end(); } - - __syscall_return_slowpath(regs); } /* Handles int $0x80 */ __visible noinstr void do_int80_syscall_32(struct pt_regs *regs) { - enter_from_user_mode(regs); - instrumentation_begin(); + unsigned int nr = syscall_32_enter(regs); - local_irq_enable(); - do_syscall_32_irqs_on(regs); - - instrumentation_end(); - exit_to_user_mode(); + do_syscall_32_irqs_on(regs, nr); + syscall_return_slowpath(regs); } -static bool __do_fast_syscall_32(struct pt_regs *regs) +static noinstr bool __do_fast_syscall_32(struct pt_regs *regs) { + unsigned int nr = syscall_32_enter(regs); int res; + instrumentation_begin(); /* Fetch EBP from where the vDSO stashed it. */ if (IS_ENABLED(CONFIG_X86_64)) { /* @@ -460,17 +458,18 @@ static bool __do_fast_syscall_32(struct pt_regs *regs) res = get_user(*(u32 *)®s->bp, (u32 __user __force *)(unsigned long)(u32)regs->sp); } + instrumentation_end(); if (res) { /* User code screwed up. */ regs->ax = -EFAULT; - local_irq_disable(); - __prepare_exit_to_usermode(regs); + syscall_return_slowpath(regs); return false; } /* Now this is just like a normal syscall. */ - do_syscall_32_irqs_on(regs); + do_syscall_32_irqs_on(regs, nr); + syscall_return_slowpath(regs); return true; } @@ -483,7 +482,6 @@ __visible noinstr long do_fast_syscall_32(struct pt_regs *regs) */ unsigned long landing_pad = (unsigned long)current->mm->context.vdso + vdso_image_32.sym_int80_landing_pad; - bool success; /* * SYSENTER loses EIP, and even SYSCALL32 needs us to skip forward @@ -492,17 +490,8 @@ __visible noinstr long do_fast_syscall_32(struct pt_regs *regs) */ regs->ip = landing_pad; - enter_from_user_mode(regs); - instrumentation_begin(); - - local_irq_enable(); - success = __do_fast_syscall_32(regs); - - instrumentation_end(); - exit_to_user_mode(); - - /* If it failed, keep it simple: use IRET. */ - if (!success) + /* Invoke the syscall. If it failed, keep it simple: use IRET. */ + if (!__do_fast_syscall_32(regs)) return 0; #ifdef CONFIG_X86_64 |