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D50414.1784109199.diff
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D50414.1784109199.diff
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diff --git a/sys/amd64/amd64/cpu_switch.S b/sys/amd64/amd64/cpu_switch.S
--- a/sys/amd64/amd64/cpu_switch.S
+++ b/sys/amd64/amd64/cpu_switch.S
@@ -91,14 +91,8 @@
jnz 2f
testb $CPUID_STDEXT_FSGSBASE,cpu_stdext_feature(%rip)
jz 2f
- movl %fs,%eax
- cmpl $KUF32SEL,%eax
- jne 1f
rdfsbase %rax
movq %rax,PCB_FSBASE(%r8)
-1: movl %gs,%eax
- cmpl $KUG32SEL,%eax
- jne 2f
movq %rdx,%r12
movl $MSR_KGSBASE,%ecx /* Read user gs base */
rdmsr
diff --git a/sys/amd64/amd64/exception.S b/sys/amd64/amd64/exception.S
--- a/sys/amd64/amd64/exception.S
+++ b/sys/amd64/amd64/exception.S
@@ -479,22 +479,14 @@
jz 6f /* already running with kernel GS.base */
testb $CPUID_STDEXT_FSGSBASE,cpu_stdext_feature(%rip)
jz 2f
- cmpw $KUF32SEL,TF_FS(%rsp)
- jne 1f
rdfsbase %rax
-1: cmpw $KUG32SEL,TF_GS(%rsp)
- jne 2f
rdgsbase %rdx
2: swapgs
lfence
movq PCPU(CURPCB),%rdi
testb $CPUID_STDEXT_FSGSBASE,cpu_stdext_feature(%rip)
jz 4f
- cmpw $KUF32SEL,TF_FS(%rsp)
- jne 3f
movq %rax,PCB_FSBASE(%rdi)
-3: cmpw $KUG32SEL,TF_GS(%rsp)
- jne 4f
movq %rdx,PCB_GSBASE(%rdi)
orl $PCB_FULL_IRET,PCB_FLAGS(%rdi) /* full iret from user #gp */
4: call handle_ibrs_entry
@@ -730,12 +722,8 @@
orl $PCB_FULL_IRET,PCB_FLAGS(%rdi)
testb $CPUID_STDEXT_FSGSBASE,cpu_stdext_feature(%rip)
jz 3f
- cmpw $KUF32SEL,TF_FS(%rsp)
- jne 2f
rdfsbase %rax
movq %rax,PCB_FSBASE(%rdi)
-2: cmpw $KUG32SEL,TF_GS(%rsp)
- jne 3f
movl $MSR_KGSBASE,%ecx
rdmsr
shlq $32,%rdx
@@ -842,12 +830,8 @@
orl $PCB_FULL_IRET,PCB_FLAGS(%rdi)
testb $CPUID_STDEXT_FSGSBASE,cpu_stdext_feature(%rip)
jz 3f
- cmpw $KUF32SEL,TF_FS(%rsp)
- jne 2f
rdfsbase %rax
movq %rax,PCB_FSBASE(%rdi)
-2: cmpw $KUG32SEL,TF_GS(%rsp)
- jne 3f
movl $MSR_KGSBASE,%ecx
rdmsr
shlq $32,%rdx
@@ -1177,15 +1161,12 @@
.globl ld_fs
ld_fs:
movw %ax,%fs
- cmpw $KUF32SEL,%ax
- jne 1f
movl $MSR_FSBASE,%ecx
movl PCB_FSBASE(%r8),%eax
movl PCB_FSBASE+4(%r8),%edx
.globl ld_fsbase
ld_fsbase:
wrmsr
-1:
/* Restore %gs and gsbase */
movw TF_GS(%rsp),%si
pushfq
@@ -1198,10 +1179,6 @@
.globl ld_gs
ld_gs:
movw %si,%gs
- /* Save user %gs base into %r14d:%r15d */
- rdmsr
- movl %eax,%r14d
- movl %edx,%r15d
/* Restore kernel %gs base */
movl %r12d,%eax
movl %r13d,%edx
@@ -1212,14 +1189,8 @@
* from the previously saved msr read.
*/
movl $MSR_KGSBASE,%ecx
- cmpw $KUG32SEL,%si
- jne 1f
movl PCB_GSBASE(%r8),%eax
movl PCB_GSBASE+4(%r8),%edx
- jmp ld_gsbase
-1:
- movl %r14d,%eax
- movl %r15d,%edx
.globl ld_gsbase
ld_gsbase:
wrmsr /* May trap if non-canonical, but only for TLS. */
diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c
--- a/sys/amd64/amd64/machdep.c
+++ b/sys/amd64/amd64/machdep.c
@@ -1789,10 +1789,8 @@
(pcb->pcb_flags & PCB_FULL_IRET) == 0) {
r = intr_disable();
if ((pcb->pcb_flags & PCB_FULL_IRET) == 0) {
- if (rfs() == _ufssel)
- pcb->pcb_fsbase = rdfsbase();
- if (rgs() == _ugssel)
- pcb->pcb_gsbase = rdmsr(MSR_KGSBASE);
+ pcb->pcb_fsbase = rdfsbase();
+ pcb->pcb_gsbase = rdmsr(MSR_KGSBASE);
}
set_pcb_flags_raw(pcb, flags);
intr_restore(r);
diff --git a/sys/amd64/ia32/ia32_exception.S b/sys/amd64/ia32/ia32_exception.S
--- a/sys/amd64/ia32/ia32_exception.S
+++ b/sys/amd64/ia32/ia32_exception.S
@@ -54,10 +54,10 @@
movq %rax,TF_RAX(%rsp)
movq %rdx,TF_RDX(%rsp)
movq %rcx,TF_RCX(%rsp)
+ movq %r15,TF_R15(%rsp)
call handle_ibrs_entry
sti
movq %rsi,TF_RSI(%rsp)
- movq %r8,TF_R8(%rsp)
movq %r9,TF_R9(%rsp)
movq %rbx,TF_RBX(%rsp)
movq %rbp,TF_RBP(%rsp)
@@ -66,7 +66,6 @@
movq %r12,TF_R12(%rsp)
movq %r13,TF_R13(%rsp)
movq %r14,TF_R14(%rsp)
- movq %r15,TF_R15(%rsp)
movl $TF_HASSEGS,TF_FLAGS(%rsp)
pushfq
andq $~(PSL_D | PSL_AC),(%rsp)

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