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d75cd22fdd
Don't conflate sysret and sysexit; they're different instructions with
different semantics, and may be in use at the same time (at least
within the same kernel, depending on whether its an Intel or AMD
system).
sysexit - just return to userspace, does no register restoration of
any kind; must explicitly atomically enable interrupts.
sysret - reloads flags from r11, so no need to explicitly enable
interrupts on 64-bit, responsible for restoring usermode %gs
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citirx.com>
Cc: xen-devel <xen-devel@lists.xensource.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
58 lines
1.8 KiB
C
58 lines
1.8 KiB
C
#include <asm/paravirt.h>
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#include <asm/asm-offsets.h>
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#include <linux/stringify.h>
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DEF_NATIVE(pv_irq_ops, irq_disable, "cli");
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DEF_NATIVE(pv_irq_ops, irq_enable, "sti");
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DEF_NATIVE(pv_irq_ops, restore_fl, "pushq %rdi; popfq");
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DEF_NATIVE(pv_irq_ops, save_fl, "pushfq; popq %rax");
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DEF_NATIVE(pv_cpu_ops, iret, "iretq");
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DEF_NATIVE(pv_mmu_ops, read_cr2, "movq %cr2, %rax");
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DEF_NATIVE(pv_mmu_ops, read_cr3, "movq %cr3, %rax");
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DEF_NATIVE(pv_mmu_ops, write_cr3, "movq %rdi, %cr3");
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DEF_NATIVE(pv_mmu_ops, flush_tlb_single, "invlpg (%rdi)");
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DEF_NATIVE(pv_cpu_ops, clts, "clts");
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DEF_NATIVE(pv_cpu_ops, wbinvd, "wbinvd");
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/* the three commands give us more control to how to return from a syscall */
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DEF_NATIVE(pv_cpu_ops, usersp_sysret, "movq %gs:" __stringify(pda_oldrsp) ", %rsp; swapgs; sysretq;");
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DEF_NATIVE(pv_cpu_ops, swapgs, "swapgs");
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unsigned native_patch(u8 type, u16 clobbers, void *ibuf,
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unsigned long addr, unsigned len)
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{
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const unsigned char *start, *end;
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unsigned ret;
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#define PATCH_SITE(ops, x) \
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case PARAVIRT_PATCH(ops.x): \
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start = start_##ops##_##x; \
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end = end_##ops##_##x; \
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goto patch_site
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switch(type) {
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PATCH_SITE(pv_irq_ops, restore_fl);
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PATCH_SITE(pv_irq_ops, save_fl);
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PATCH_SITE(pv_irq_ops, irq_enable);
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PATCH_SITE(pv_irq_ops, irq_disable);
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PATCH_SITE(pv_cpu_ops, iret);
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PATCH_SITE(pv_cpu_ops, usersp_sysret);
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PATCH_SITE(pv_cpu_ops, swapgs);
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PATCH_SITE(pv_mmu_ops, read_cr2);
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PATCH_SITE(pv_mmu_ops, read_cr3);
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PATCH_SITE(pv_mmu_ops, write_cr3);
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PATCH_SITE(pv_cpu_ops, clts);
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PATCH_SITE(pv_mmu_ops, flush_tlb_single);
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PATCH_SITE(pv_cpu_ops, wbinvd);
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patch_site:
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ret = paravirt_patch_insns(ibuf, len, start, end);
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break;
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default:
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ret = paravirt_patch_default(type, clobbers, ibuf, addr, len);
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break;
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}
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#undef PATCH_SITE
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return ret;
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}
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