From: Brian Gerst <brgerst@gmail.com>
To: linux-kernel@vger.kernel.org, x86@kernel.org
Cc: Andy Lutomirski <luto@kernel.org>, Borislav Petkov <bp@alien8.de>,
Thomas Gleixner <tglx@linutronix.de>,
"H . Peter Anvin" <hpa@zytor.com>,
Peter Zijlstra <peterz@infradead.org>,
Brian Gerst <brgerst@gmail.com>
Subject: [PATCH 3/4] x86-32: Remove lazy GS macros
Date: Fri, 25 Mar 2022 11:39:52 -0400 [thread overview]
Message-ID: <20220325153953.162643-4-brgerst@gmail.com> (raw)
In-Reply-To: <20220325153953.162643-1-brgerst@gmail.com>
GS is always a user segment now.
Signed-off-by: Brian Gerst <brgerst@gmail.com>
---
arch/x86/include/asm/mmu_context.h | 2 +-
arch/x86/include/asm/segment.h | 5 -----
arch/x86/kernel/process.c | 5 +----
arch/x86/kernel/process_32.c | 11 ++++-------
arch/x86/kernel/ptrace.c | 6 +++---
arch/x86/kernel/signal.c | 8 +++++---
arch/x86/kernel/vm86_32.c | 4 ++--
arch/x86/lib/insn-eval.c | 5 +++--
arch/x86/math-emu/get_address.c | 2 +-
9 files changed, 20 insertions(+), 28 deletions(-)
diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h
index 27516046117a..b8d40ddeab00 100644
--- a/arch/x86/include/asm/mmu_context.h
+++ b/arch/x86/include/asm/mmu_context.h
@@ -141,7 +141,7 @@ do { \
#ifdef CONFIG_X86_32
#define deactivate_mm(tsk, mm) \
do { \
- lazy_load_gs(0); \
+ loadsegment(gs, 0); \
} while (0)
#else
#define deactivate_mm(tsk, mm) \
diff --git a/arch/x86/include/asm/segment.h b/arch/x86/include/asm/segment.h
index 656ed6531d03..617b3663e4dd 100644
--- a/arch/x86/include/asm/segment.h
+++ b/arch/x86/include/asm/segment.h
@@ -354,11 +354,6 @@ static inline void __loadsegment_fs(unsigned short value)
* x86-32 user GS accessors. This is ugly and could do with some cleaning up.
*/
#ifdef CONFIG_X86_32
-# define get_user_gs(regs) (u16)({ unsigned long v; savesegment(gs, v); v; })
-# define set_user_gs(regs, v) loadsegment(gs, (unsigned long)(v))
-# define task_user_gs(tsk) ((tsk)->thread.gs)
-# define lazy_save_gs(v) savesegment(gs, (v))
-# define lazy_load_gs(v) loadsegment(gs, (v))
# define load_gs_index(v) loadsegment(gs, (v))
#endif /* X86_32 */
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index b370767f5b19..96a9885b9c3a 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -160,6 +160,7 @@ int copy_thread(unsigned long clone_flags, unsigned long sp, unsigned long arg,
savesegment(ds, p->thread.ds);
#else
p->thread.sp0 = (unsigned long) (childregs + 1);
+ savesegment(gs, p->thread.gs);
/*
* Clear all status flags including IF and set fixed bit. 64bit
* does not have this initialization as the frame does not contain
@@ -191,10 +192,6 @@ int copy_thread(unsigned long clone_flags, unsigned long sp, unsigned long arg,
if (sp)
childregs->sp = sp;
-#ifdef CONFIG_X86_32
- task_user_gs(p) = get_user_gs(current_pt_regs());
-#endif
-
if (unlikely(p->flags & PF_IO_WORKER)) {
/*
* An IO thread is a user space thread, but it doesn't
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 26edb1cd07a4..877358f3dba7 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -63,10 +63,7 @@ void __show_regs(struct pt_regs *regs, enum show_regs_mode mode,
unsigned long d0, d1, d2, d3, d6, d7;
unsigned short gs;
- if (user_mode(regs))
- gs = get_user_gs(regs);
- else
- savesegment(gs, gs);
+ savesegment(gs, gs);
show_ip(regs, log_lvl);
@@ -114,7 +111,7 @@ void release_thread(struct task_struct *dead_task)
void
start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
{
- set_user_gs(regs, 0);
+ loadsegment(gs, 0);
regs->fs = 0;
regs->ds = __USER_DS;
regs->es = __USER_DS;
@@ -177,7 +174,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
* used %fs or %gs (it does not today), or if the kernel is
* running inside of a hypervisor layer.
*/
- lazy_save_gs(prev->gs);
+ savesegment(gs, prev->gs);
/*
* Load the per-thread Thread-Local Storage descriptor.
@@ -208,7 +205,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
* Restore %gs if needed (which is common)
*/
if (prev->gs | next->gs)
- lazy_load_gs(next->gs);
+ loadsegment(gs, next->gs);
this_cpu_write(current_task, next_p);
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 8d2f2f995539..a2336db1aac1 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -171,9 +171,9 @@ static u16 get_segment_reg(struct task_struct *task, unsigned long offset)
retval = *pt_regs_access(task_pt_regs(task), offset);
else {
if (task == current)
- retval = get_user_gs(task_pt_regs(task));
+ savesegment(gs, retval);
else
- retval = task_user_gs(task);
+ retval = task->thread.gs;
}
return retval;
}
@@ -211,7 +211,7 @@ static int set_segment_reg(struct task_struct *task,
break;
case offsetof(struct user_regs_struct, gs):
- task_user_gs(task) = value;
+ task->thread.gs = value;
}
return 0;
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index ec71e06ae364..add4bb6f9d43 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -94,7 +94,7 @@ static bool restore_sigcontext(struct pt_regs *regs,
return false;
#ifdef CONFIG_X86_32
- set_user_gs(regs, sc.gs);
+ loadsegment(gs, sc.gs);
regs->fs = sc.fs;
regs->es = sc.es;
regs->ds = sc.ds;
@@ -147,8 +147,10 @@ __unsafe_setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
struct pt_regs *regs, unsigned long mask)
{
#ifdef CONFIG_X86_32
- unsafe_put_user(get_user_gs(regs),
- (unsigned int __user *)&sc->gs, Efault);
+ unsigned int gs;
+ savesegment(gs, gs);
+
+ unsafe_put_user(gs, (unsigned int __user *)&sc->gs, Efault);
unsafe_put_user(regs->fs, (unsigned int __user *)&sc->fs, Efault);
unsafe_put_user(regs->es, (unsigned int __user *)&sc->es, Efault);
unsafe_put_user(regs->ds, (unsigned int __user *)&sc->ds, Efault);
diff --git a/arch/x86/kernel/vm86_32.c b/arch/x86/kernel/vm86_32.c
index c21bcd668284..e9e803a4d44c 100644
--- a/arch/x86/kernel/vm86_32.c
+++ b/arch/x86/kernel/vm86_32.c
@@ -151,7 +151,7 @@ void save_v86_state(struct kernel_vm86_regs *regs, int retval)
memcpy(®s->pt, &vm86->regs32, sizeof(struct pt_regs));
- lazy_load_gs(vm86->regs32.gs);
+ loadsegment(gs, vm86->regs32.gs);
regs->pt.ax = retval;
return;
@@ -325,7 +325,7 @@ static long do_sys_vm86(struct vm86plus_struct __user *user_vm86, bool plus)
* Save old state
*/
vm86->saved_sp0 = tsk->thread.sp0;
- lazy_save_gs(vm86->regs32.gs);
+ savesegment(gs, vm86->regs32.gs);
/* make room for real-mode segments */
preempt_disable();
diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c
index b781d324211b..21104c41cba0 100644
--- a/arch/x86/lib/insn-eval.c
+++ b/arch/x86/lib/insn-eval.c
@@ -342,9 +342,9 @@ static int resolve_seg_reg(struct insn *insn, struct pt_regs *regs, int regoff)
*/
static short get_segment_selector(struct pt_regs *regs, int seg_reg_idx)
{
-#ifdef CONFIG_X86_64
unsigned short sel;
+#ifdef CONFIG_X86_64
switch (seg_reg_idx) {
case INAT_SEG_REG_IGNORE:
return 0;
@@ -402,7 +402,8 @@ static short get_segment_selector(struct pt_regs *regs, int seg_reg_idx)
case INAT_SEG_REG_FS:
return (unsigned short)(regs->fs & 0xffff);
case INAT_SEG_REG_GS:
- return get_user_gs(regs);
+ savesegment(gs, sel);
+ return sel;
case INAT_SEG_REG_IGNORE:
default:
return -EINVAL;
diff --git a/arch/x86/math-emu/get_address.c b/arch/x86/math-emu/get_address.c
index b82ca14ba718..4a9fd9029a53 100644
--- a/arch/x86/math-emu/get_address.c
+++ b/arch/x86/math-emu/get_address.c
@@ -153,7 +153,7 @@ static long pm_address(u_char FPU_modrm, u_char segment,
switch (segment) {
case PREFIX_GS_ - 1:
/* user gs handling can be lazy, use special accessors */
- addr->selector = get_user_gs(FPU_info->regs);
+ savesegment(gs, addr->selector);
break;
default:
addr->selector = PM_REG_(segment);
--
2.35.1
next prev parent reply other threads:[~2022-03-25 15:44 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-25 15:39 [PATCH 0/4] x86-32: Clean up GS segment handling Brian Gerst
2022-03-25 15:39 ` [PATCH 1/4] x86-32: Simplify ELF_CORE_COPY_REGS Brian Gerst
2022-04-15 9:42 ` [tip: x86/core] x86/32: " tip-bot2 for Brian Gerst
2022-03-25 15:39 ` [PATCH 2/4] ELF: Remove elf_core_copy_kernel_regs() Brian Gerst
2022-04-13 11:41 ` Borislav Petkov
2022-04-13 11:41 ` Borislav Petkov
2022-04-13 12:31 ` Michael Ellerman
2022-04-13 12:31 ` Michael Ellerman
2022-04-15 9:42 ` [tip: x86/core] " tip-bot2 for Brian Gerst
2022-03-25 15:39 ` Brian Gerst [this message]
2022-04-15 9:42 ` [tip: x86/core] x86/32: Remove lazy GS macros tip-bot2 for Brian Gerst
2022-03-25 15:39 ` [PATCH 4/4] x86: Merge load_gs_index() Brian Gerst
2022-04-15 9:42 ` [tip: x86/core] x86/asm: " tip-bot2 for Brian Gerst
2022-03-25 15:45 ` [PATCH 0/4] x86-32: Clean up GS segment handling Andy Lutomirski
2022-04-05 16:12 ` Thomas Gleixner
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20220325153953.162643-4-brgerst@gmail.com \
--to=brgerst@gmail.com \
--cc=bp@alien8.de \
--cc=hpa@zytor.com \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@kernel.org \
--cc=peterz@infradead.org \
--cc=tglx@linutronix.de \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.