| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <1447970147-1733-4-git-send-email-boris.ostrovsky@oracle.com>
Date: Thu, 19 Nov 2015 16:55:47 -0500
From: Boris Ostrovsky <boris.ostrovsky@...cle.com>
To: tglx@...utronix.de, mingo@...hat.com, hpa@...or.com,
david.vrabel@...rix.com, konrad.wilk@...cle.com
Cc: luto@...nel.org, bp@...e.de, linux-kernel@...r.kernel.org,
xen-devel@...ts.xenproject.org,
virtualization@...ts.linux-foundation.org,
Boris Ostrovsky <boris.ostrovsky@...cle.com>
Subject: [PATCH v2 3/3] x86: usergs_sysret32 pv op is no longer needed
As result of commit "x86/xen: Avoid fast syscall path for Xen PV guests"
usergs_sysret32 pv op is not called by Xen PV guests anymore and
since they were the only ones who used it we can safely remove it.
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@...cle.com>
---
arch/x86/entry/entry_64_compat.S | 10 ++--------
arch/x86/include/asm/paravirt.h | 5 -----
arch/x86/include/asm/paravirt_types.h | 8 --------
arch/x86/kernel/asm-offsets_64.c | 1 -
arch/x86/kernel/paravirt.c | 5 -----
arch/x86/kernel/paravirt_patch_64.c | 2 --
arch/x86/xen/xen-asm_64.S | 19 -------------------
7 files changed, 2 insertions(+), 48 deletions(-)
diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S
index 402e34a..bbcb285 100644
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -18,13 +18,6 @@
.section .entry.text, "ax"
-#ifdef CONFIG_PARAVIRT
-ENTRY(native_usergs_sysret32)
- swapgs
- sysretl
-ENDPROC(native_usergs_sysret32)
-#endif
-
/*
* 32-bit SYSENTER instruction entry.
*
@@ -238,7 +231,8 @@ sysret32_from_system_call:
xorq %r9, %r9
xorq %r10, %r10
movq RSP-ORIG_RAX(%rsp), %rsp
- USERGS_SYSRET32
+ swapgs
+ sysretl
END(entry_SYSCALL_compat)
/*
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index c28518e..1b71c3a 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -922,11 +922,6 @@ extern void default_banner(void);
call PARA_INDIRECT(pv_irq_ops+PV_IRQ_irq_enable); \
PV_RESTORE_REGS(clobbers | CLBR_CALLEE_SAVE);)
-#define USERGS_SYSRET32 \
- PARA_SITE(PARA_PATCH(pv_cpu_ops, PV_CPU_usergs_sysret32), \
- CLBR_NONE, \
- jmp PARA_INDIRECT(pv_cpu_ops+PV_CPU_usergs_sysret32))
-
#ifdef CONFIG_X86_32
#define GET_CR0_INTO_EAX \
push %ecx; push %edx; \
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index 608bbf3..702c8bd 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -165,14 +165,6 @@ struct pv_cpu_ops {
*/
void (*usergs_sysret64)(void);
- /*
- * Switch to usermode gs and return to 32-bit usermode using
- * sysret. Used to return to 32-on-64 compat processes.
- * Other usermode register state, including %esp, must already
- * be restored.
- */
- void (*usergs_sysret32)(void);
-
/* Normal iret. Jump to this with the standard iret stack
frame set up. */
void (*iret)(void);
diff --git a/arch/x86/kernel/asm-offsets_64.c b/arch/x86/kernel/asm-offsets_64.c
index d8f42f9..f2edafb 100644
--- a/arch/x86/kernel/asm-offsets_64.c
+++ b/arch/x86/kernel/asm-offsets_64.c
@@ -23,7 +23,6 @@ int main(void)
{
#ifdef CONFIG_PARAVIRT
OFFSET(PV_IRQ_adjust_exception_frame, pv_irq_ops, adjust_exception_frame);
- OFFSET(PV_CPU_usergs_sysret32, pv_cpu_ops, usergs_sysret32);
OFFSET(PV_CPU_usergs_sysret64, pv_cpu_ops, usergs_sysret64);
OFFSET(PV_CPU_swapgs, pv_cpu_ops, swapgs);
BLANK();
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index c55f437..8c19b4d 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -162,7 +162,6 @@ unsigned paravirt_patch_default(u8 type, u16 clobbers, void *insnbuf,
ret = paravirt_patch_ident_64(insnbuf, len);
else if (type == PARAVIRT_PATCH(pv_cpu_ops.iret) ||
- type == PARAVIRT_PATCH(pv_cpu_ops.usergs_sysret32) ||
type == PARAVIRT_PATCH(pv_cpu_ops.usergs_sysret64))
/* If operation requires a jmp, then jmp */
ret = paravirt_patch_jmp(insnbuf, opfunc, addr, len);
@@ -217,7 +216,6 @@ static u64 native_steal_clock(int cpu)
/* These are in entry.S */
extern void native_iret(void);
-extern void native_usergs_sysret32(void);
extern void native_usergs_sysret64(void);
static struct resource reserve_ioports = {
@@ -376,9 +374,6 @@ __visible struct pv_cpu_ops pv_cpu_ops = {
.load_sp0 = native_load_sp0,
#ifdef CONFIG_X86_64
-#ifdef CONFIG_IA32_EMULATION
- .usergs_sysret32 = native_usergs_sysret32,
-#endif
.usergs_sysret64 = native_usergs_sysret64,
#endif
.iret = native_iret,
diff --git a/arch/x86/kernel/paravirt_patch_64.c b/arch/x86/kernel/paravirt_patch_64.c
index 17c00f8..e70087a 100644
--- a/arch/x86/kernel/paravirt_patch_64.c
+++ b/arch/x86/kernel/paravirt_patch_64.c
@@ -14,7 +14,6 @@ DEF_NATIVE(pv_cpu_ops, clts, "clts");
DEF_NATIVE(pv_cpu_ops, wbinvd, "wbinvd");
DEF_NATIVE(pv_cpu_ops, usergs_sysret64, "swapgs; sysretq");
-DEF_NATIVE(pv_cpu_ops, usergs_sysret32, "swapgs; sysretl");
DEF_NATIVE(pv_cpu_ops, swapgs, "swapgs");
DEF_NATIVE(, mov32, "mov %edi, %eax");
@@ -54,7 +53,6 @@ unsigned native_patch(u8 type, u16 clobbers, void *ibuf,
PATCH_SITE(pv_irq_ops, save_fl);
PATCH_SITE(pv_irq_ops, irq_enable);
PATCH_SITE(pv_irq_ops, irq_disable);
- PATCH_SITE(pv_cpu_ops, usergs_sysret32);
PATCH_SITE(pv_cpu_ops, usergs_sysret64);
PATCH_SITE(pv_cpu_ops, swapgs);
PATCH_SITE(pv_mmu_ops, read_cr2);
diff --git a/arch/x86/xen/xen-asm_64.S b/arch/x86/xen/xen-asm_64.S
index f22667a..cc8acc4 100644
--- a/arch/x86/xen/xen-asm_64.S
+++ b/arch/x86/xen/xen-asm_64.S
@@ -68,25 +68,6 @@ ENTRY(xen_sysret64)
ENDPATCH(xen_sysret64)
RELOC(xen_sysret64, 1b+1)
-ENTRY(xen_sysret32)
- /*
- * We're already on the usermode stack at this point, but
- * still with the kernel gs, so we can easily switch back
- */
- movq %rsp, PER_CPU_VAR(rsp_scratch)
- movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
-
- pushq $__USER32_DS
- pushq PER_CPU_VAR(rsp_scratch)
- pushq %r11
- pushq $__USER32_CS
- pushq %rcx
-
- pushq $0
-1: jmp hypercall_iret
-ENDPATCH(xen_sysret32)
-RELOC(xen_sysret32, 1b+1)
-
/*
* Xen handles syscall callbacks much like ordinary exceptions, which
* means we have:
--
1.8.1.4
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists