savectx() has not been used for fork(2) for about 15 years. [1]
Do not clobber FPU thread's PCB as it is more harmful. When we resume CPU, unconditionally reload FPU state. Pointed out by: bde [1]
This commit is contained in:
jkim
parent
3327e87142
commit
c530d20c6a
@ -34,11 +34,11 @@
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#include "acpi_wakedata.h"
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#include "assym.s"
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#define WAKEUP_CTX(member) wakeup_ ## member - wakeup_ctx(%rdi)
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#define WAKEUP_CTX(member) wakeup_ ## member - wakeup_ctx(%rsi)
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ENTRY(acpi_restorecpu)
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/* Switch to KPML4phys. */
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movq %rsi, %rax
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movq %rdi, %rax
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movq %rax, %cr3
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/* Restore GDT. */
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@ -47,7 +47,7 @@ ENTRY(acpi_restorecpu)
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1:
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/* Fetch PCB. */
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movq WAKEUP_CTX(pcb), %rsi
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movq WAKEUP_CTX(pcb), %rdi
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/* Force kernel segment registers. */
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movl $KDSEL, %eax
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@ -60,16 +60,16 @@ ENTRY(acpi_restorecpu)
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movw %ax, %gs
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movl $MSR_FSBASE, %ecx
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movl PCB_FSBASE(%rsi), %eax
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movl 4 + PCB_FSBASE(%rsi), %edx
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movl PCB_FSBASE(%rdi), %eax
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movl 4 + PCB_FSBASE(%rdi), %edx
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wrmsr
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movl $MSR_GSBASE, %ecx
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movl PCB_GSBASE(%rsi), %eax
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movl 4 + PCB_GSBASE(%rsi), %edx
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movl PCB_GSBASE(%rdi), %eax
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movl 4 + PCB_GSBASE(%rdi), %edx
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wrmsr
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movl $MSR_KGSBASE, %ecx
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movl PCB_KGSBASE(%rsi), %eax
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movl 4 + PCB_KGSBASE(%rsi), %edx
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movl PCB_KGSBASE(%rdi), %eax
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movl 4 + PCB_KGSBASE(%rdi), %edx
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wrmsr
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/* Restore EFER. */
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@ -101,20 +101,20 @@ ENTRY(acpi_restorecpu)
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wrmsr
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/* Restore CR0 except for FPU mode. */
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movq PCB_CR0(%rsi), %rax
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movq PCB_CR0(%rdi), %rax
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movq %rax, %rcx
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andq $~(CR0_EM | CR0_TS), %rax
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movq %rax, %cr0
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/* Restore CR2 and CR4. */
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movq PCB_CR2(%rsi), %rax
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movq PCB_CR2(%rdi), %rax
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movq %rax, %cr2
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movq PCB_CR4(%rsi), %rax
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movq PCB_CR4(%rdi), %rax
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movq %rax, %cr4
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/* Restore descriptor tables. */
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lidt PCB_IDT(%rsi)
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lldt PCB_LDT(%rsi)
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lidt PCB_IDT(%rdi)
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lldt PCB_LDT(%rdi)
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#define SDT_SYSTSS 9
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#define SDT_SYSBSY 11
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@ -122,58 +122,44 @@ ENTRY(acpi_restorecpu)
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/* Clear "task busy" bit and reload TR. */
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movq PCPU(TSS), %rax
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andb $(~SDT_SYSBSY | SDT_SYSTSS), 5(%rax)
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movw PCB_TR(%rsi), %ax
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movw PCB_TR(%rdi), %ax
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ltr %ax
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#undef SDT_SYSTSS
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#undef SDT_SYSBSY
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/* Restore other callee saved registers. */
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movq PCB_R15(%rsi), %r15
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movq PCB_R14(%rsi), %r14
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movq PCB_R13(%rsi), %r13
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movq PCB_R12(%rsi), %r12
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movq PCB_RBP(%rsi), %rbp
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movq PCB_RSP(%rsi), %rsp
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movq PCB_RBX(%rsi), %rbx
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movq PCB_R15(%rdi), %r15
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movq PCB_R14(%rdi), %r14
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movq PCB_R13(%rdi), %r13
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movq PCB_R12(%rdi), %r12
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movq PCB_RBP(%rdi), %rbp
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movq PCB_RSP(%rdi), %rsp
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movq PCB_RBX(%rdi), %rbx
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/* Restore debug registers. */
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movq PCB_DR0(%rsi), %rax
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movq PCB_DR0(%rdi), %rax
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movq %rax, %dr0
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movq PCB_DR1(%rsi), %rax
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movq PCB_DR1(%rdi), %rax
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movq %rax, %dr1
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movq PCB_DR2(%rsi), %rax
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movq PCB_DR2(%rdi), %rax
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movq %rax, %dr2
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movq PCB_DR3(%rsi), %rax
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movq PCB_DR3(%rdi), %rax
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movq %rax, %dr3
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movq PCB_DR6(%rsi), %rax
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movq PCB_DR6(%rdi), %rax
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movq %rax, %dr6
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movq PCB_DR7(%rsi), %rax
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movq PCB_DR7(%rdi), %rax
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movq %rax, %dr7
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#define __INITIAL_FPUCW__ 0x037f
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#define __INITIAL_MXCSR__ 0x1f80
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/* Initialize FPU and restore state if necessary. */
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/* Restore FPU state. */
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fninit
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movw $__INITIAL_FPUCW__, -2(%rsp)
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fldcw -2(%rsp)
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movl $__INITIAL_MXCSR__, -4(%rsp)
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ldmxcsr -4(%rsp)
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movq PCPU(FPCURTHREAD), %rax
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testq %rax, %rax
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je 1f
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fxrstor PCB_USERFPU(%rsi)
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1:
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#undef __INITIAL_FPUCW__
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#undef __INITIAL_MXCSR__
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fxrstor PCB_USERFPU(%rdi)
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/* Reload CR0. */
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movq %rcx, %cr0
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/* Restore return address. */
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movq PCB_RIP(%rsi), %rax
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movq PCB_RIP(%rdi), %rax
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movq %rax, (%rsp)
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/* Indicate the CPU is resumed. */
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@ -210,8 +210,8 @@ wakeup_64:
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mov %ax, %ds
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/* Restore arguments and return. */
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movq wakeup_ctx - wakeup_start(%rbx), %rdi
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movq wakeup_kpml4 - wakeup_start(%rbx), %rsi
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movq wakeup_kpml4 - wakeup_start(%rbx), %rdi
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movq wakeup_ctx - wakeup_start(%rbx), %rsi
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movq wakeup_retaddr - wakeup_start(%rbx), %rax
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jmp *%rax
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@ -302,93 +302,65 @@ END(cpu_switch)
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* Update pcb, saving current processor state.
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*/
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ENTRY(savectx)
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/* Fetch PCB. */
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movq %rdi,%rsi
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/* Save caller's return address. */
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movq (%rsp),%rax
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movq %rax,PCB_RIP(%rsi)
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movq %rax,PCB_RIP(%rdi)
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movq %rbx,PCB_RBX(%rsi)
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movq %rsp,PCB_RSP(%rsi)
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movq %rbp,PCB_RBP(%rsi)
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movq %r12,PCB_R12(%rsi)
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movq %r13,PCB_R13(%rsi)
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movq %r14,PCB_R14(%rsi)
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movq %r15,PCB_R15(%rsi)
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movq %rbx,PCB_RBX(%rdi)
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movq %rsp,PCB_RSP(%rdi)
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movq %rbp,PCB_RBP(%rdi)
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movq %r12,PCB_R12(%rdi)
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movq %r13,PCB_R13(%rdi)
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movq %r14,PCB_R14(%rdi)
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movq %r15,PCB_R15(%rdi)
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movq %cr0,%rsi
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movq %rsi,PCB_CR0(%rdi)
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movq %cr2,%rax
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movq %rax,PCB_CR2(%rsi)
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movq %rax,PCB_CR2(%rdi)
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movq %cr3,%rax
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movq %rax,PCB_CR3(%rsi)
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movq %rax,PCB_CR3(%rdi)
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movq %cr4,%rax
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movq %rax,PCB_CR4(%rsi)
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movq %rax,PCB_CR4(%rdi)
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movq %dr0,%rax
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movq %rax,PCB_DR0(%rsi)
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movq %rax,PCB_DR0(%rdi)
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movq %dr1,%rax
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movq %rax,PCB_DR1(%rsi)
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movq %rax,PCB_DR1(%rdi)
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movq %dr2,%rax
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movq %rax,PCB_DR2(%rsi)
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movq %rax,PCB_DR2(%rdi)
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movq %dr3,%rax
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movq %rax,PCB_DR3(%rsi)
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movq %rax,PCB_DR3(%rdi)
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movq %dr6,%rax
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movq %rax,PCB_DR6(%rsi)
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movq %rax,PCB_DR6(%rdi)
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movq %dr7,%rax
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movq %rax,PCB_DR7(%rsi)
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movq %rax,PCB_DR7(%rdi)
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movl $MSR_FSBASE,%ecx
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rdmsr
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shlq $32,%rdx
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leaq (%rax,%rdx),%rax
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movq %rax,PCB_FSBASE(%rsi)
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movq %rax,PCB_FSBASE(%rdi)
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movl $MSR_GSBASE,%ecx
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rdmsr
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shlq $32,%rdx
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leaq (%rax,%rdx),%rax
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movq %rax,PCB_GSBASE(%rsi)
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movq %rax,PCB_GSBASE(%rdi)
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movl $MSR_KGSBASE,%ecx
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rdmsr
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shlq $32,%rdx
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leaq (%rax,%rdx),%rax
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movq %rax,PCB_KGSBASE(%rsi)
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movq %rax,PCB_KGSBASE(%rdi)
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sgdt PCB_GDT(%rsi)
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sidt PCB_IDT(%rsi)
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sldt PCB_LDT(%rsi)
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str PCB_TR(%rsi)
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sgdt PCB_GDT(%rdi)
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sidt PCB_IDT(%rdi)
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sldt PCB_LDT(%rdi)
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str PCB_TR(%rdi)
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movq %cr0,%rax
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movq %rax,PCB_CR0(%rsi)
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leaq PCB_USERFPU(%rsi),%rdi
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pushfq
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cli
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clts
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fxsave (%rdi)
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movq %rax,%cr0
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fxsave PCB_USERFPU(%rdi)
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movq %rsi,%cr0 /* The previous %cr0 is saved in %rsi. */
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/*
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* If fpcurthread == NULL, then the fpu h/w state is irrelevant and the
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* state had better already be in the pcb. This is true for forks
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* but not for dumps (the old book-keeping with FP flags in the pcb
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* always lost for dumps because the dump pcb has 0 flags).
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*
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* If fpcurthread != NULL, then we have to copy the fpu h/w state to
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* fpcurthread's pcb, or reload from the requested pcb. Copying is
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* easier because we would have to handle h/w bugs for reloading.
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*/
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movq PCPU(FPCURTHREAD),%rax
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testq %rax,%rax
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je 1f
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/* arg 1 (%rdi) already loaded */
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movq TD_PCB(%rax),%rax
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movq PCB_SAVEFPU(%rax),%rsi /* arg 2 */
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movq $PCB_SAVEFPU_SIZE,%rdx /* arg 3 */
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call bcopy
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1:
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popfq
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movl $1,%eax
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ret
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END(savectx)
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