From 99504819fc643160afd6813921b1d42b18e52a49 Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Fri, 28 Jul 2017 06:00:32 -0700 Subject: [PATCH] x86/asm/32: Remove a bunch of '& 0xffff' from pt_regs segment reads Now that pt_regs properly defines segment fields as 16-bit on 32-bit CPUs, there's no need to mask off the high word. Signed-off-by: Andy Lutomirski Cc: Borislav Petkov Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Ingo Molnar --- arch/x86/ia32/ia32_signal.c | 2 +- arch/x86/include/asm/elf.h | 10 +++++----- arch/x86/kernel/dumpstack.c | 2 +- arch/x86/kernel/process_32.c | 2 +- arch/x86/kernel/process_64.c | 3 +-- arch/x86/kernel/signal.c | 2 +- arch/x86/kernel/step.c | 2 +- arch/x86/mm/extable.c | 2 +- 8 files changed, 12 insertions(+), 13 deletions(-) diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c index 724153797209..e0bb46c02857 100644 --- a/arch/x86/ia32/ia32_signal.c +++ b/arch/x86/ia32/ia32_signal.c @@ -226,7 +226,7 @@ static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, if (ksig->ka.sa.sa_flags & SA_ONSTACK) sp = sigsp(sp, ksig); /* This is the legacy signal stack switching. */ - else if ((regs->ss & 0xffff) != __USER32_DS && + else if (regs->ss != __USER32_DS && !(ksig->ka.sa.sa_flags & SA_RESTORER) && ksig->ka.sa.sa_restorer) sp = (unsigned long) ksig->ka.sa.sa_restorer; diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h index 1c18d83d3f09..a62a12c47233 100644 --- a/arch/x86/include/asm/elf.h +++ b/arch/x86/include/asm/elf.h @@ -126,15 +126,15 @@ do { \ pr_reg[4] = regs->di; \ pr_reg[5] = regs->bp; \ pr_reg[6] = regs->ax; \ - pr_reg[7] = regs->ds & 0xffff; \ - pr_reg[8] = regs->es & 0xffff; \ - pr_reg[9] = regs->fs & 0xffff; \ + pr_reg[7] = regs->ds; \ + pr_reg[8] = regs->es; \ + pr_reg[9] = regs->fs; \ pr_reg[11] = regs->orig_ax; \ pr_reg[12] = regs->ip; \ - pr_reg[13] = regs->cs & 0xffff; \ + pr_reg[13] = regs->cs; \ pr_reg[14] = regs->flags; \ pr_reg[15] = regs->sp; \ - pr_reg[16] = regs->ss & 0xffff; \ + pr_reg[16] = regs->ss; \ } while (0); #define ELF_CORE_COPY_REGS(pr_reg, regs) \ diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c index bd265a4cf108..f13b4c00a5de 100644 --- a/arch/x86/kernel/dumpstack.c +++ b/arch/x86/kernel/dumpstack.c @@ -267,7 +267,7 @@ int __die(const char *str, struct pt_regs *regs, long err) #ifdef CONFIG_X86_32 if (user_mode(regs)) { sp = regs->sp; - ss = regs->ss & 0xffff; + ss = regs->ss; } else { sp = kernel_stack_pointer(regs); savesegment(ss, ss); diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c index c6d6dc5f8bb2..efc5eeb58292 100644 --- a/arch/x86/kernel/process_32.c +++ b/arch/x86/kernel/process_32.c @@ -68,7 +68,7 @@ void __show_regs(struct pt_regs *regs, int all) if (user_mode(regs)) { sp = regs->sp; - ss = regs->ss & 0xffff; + ss = regs->ss; gs = get_user_gs(regs); } else { sp = kernel_stack_pointer(regs); diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 2987e3991c2b..e04941fb67fb 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -69,8 +69,7 @@ void __show_regs(struct pt_regs *regs, int all) unsigned int fsindex, gsindex; unsigned int ds, cs, es; - printk(KERN_DEFAULT "RIP: %04lx:%pS\n", regs->cs & 0xffff, - (void *)regs->ip); + printk(KERN_DEFAULT "RIP: %04lx:%pS\n", regs->cs, (void *)regs->ip); printk(KERN_DEFAULT "RSP: %04lx:%016lx EFLAGS: %08lx", regs->ss, regs->sp, regs->flags); if (regs->orig_ax != -1) diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c index cc30a74e4adb..e04442345fc0 100644 --- a/arch/x86/kernel/signal.c +++ b/arch/x86/kernel/signal.c @@ -256,7 +256,7 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size, sp = current->sas_ss_sp + current->sas_ss_size; } else if (IS_ENABLED(CONFIG_X86_32) && !onsigstack && - (regs->ss & 0xffff) != __USER_DS && + regs->ss != __USER_DS && !(ka->sa.sa_flags & SA_RESTORER) && ka->sa.sa_restorer) { /* This is the legacy signal stack switching. */ diff --git a/arch/x86/kernel/step.c b/arch/x86/kernel/step.c index 5f25cfbd952e..5ee663836c08 100644 --- a/arch/x86/kernel/step.c +++ b/arch/x86/kernel/step.c @@ -13,7 +13,7 @@ unsigned long convert_ip_to_linear(struct task_struct *child, struct pt_regs *re unsigned long addr, seg; addr = regs->ip; - seg = regs->cs & 0xffff; + seg = regs->cs; if (v8086_mode(regs)) { addr = (addr & 0xffff) + (seg << 4); return addr; diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c index 0ea8afcb929c..fb2ddcdf7c73 100644 --- a/arch/x86/mm/extable.c +++ b/arch/x86/mm/extable.c @@ -142,7 +142,7 @@ void __init early_fixup_exception(struct pt_regs *regs, int trapnr) * undefined. I'm not sure which CPUs do this, but at least * the 486 DX works this way. */ - if ((regs->cs & 0xFFFF) != __KERNEL_CS) + if (regs->cs != __KERNEL_CS) goto fail; /*