tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2#include <linux/stringify.h>
3
4#include <asm/paravirt.h>
5#include <asm/asm-offsets.h>
6
7#define PSTART(d, m) \
8 patch_data_##d.m
9
10#define PEND(d, m) \
11 (PSTART(d, m) + sizeof(patch_data_##d.m))
12
13#define PATCH(d, m, insn_buff, len) \
14 paravirt_patch_insns(insn_buff, len, PSTART(d, m), PEND(d, m))
15
16#define PATCH_CASE(ops, m, data, insn_buff, len) \
17 case PARAVIRT_PATCH(ops.m): \
18 return PATCH(data, ops##_##m, insn_buff, len)
19
20#ifdef CONFIG_PARAVIRT_XXL
21struct patch_xxl {
22 const unsigned char irq_irq_disable[1];
23 const unsigned char irq_irq_enable[1];
24 const unsigned char irq_save_fl[2];
25 const unsigned char mmu_read_cr2[3];
26 const unsigned char mmu_read_cr3[3];
27 const unsigned char mmu_write_cr3[3];
28 const unsigned char irq_restore_fl[2];
29# ifdef CONFIG_X86_64
30 const unsigned char cpu_wbinvd[2];
31 const unsigned char cpu_usergs_sysret64[6];
32 const unsigned char cpu_swapgs[3];
33 const unsigned char mov64[3];
34# else
35 const unsigned char cpu_iret[1];
36# endif
37};
38
39static const struct patch_xxl patch_data_xxl = {
40 .irq_irq_disable = { 0xfa }, // cli
41 .irq_irq_enable = { 0xfb }, // sti
42 .irq_save_fl = { 0x9c, 0x58 }, // pushf; pop %[re]ax
43 .mmu_read_cr2 = { 0x0f, 0x20, 0xd0 }, // mov %cr2, %[re]ax
44 .mmu_read_cr3 = { 0x0f, 0x20, 0xd8 }, // mov %cr3, %[re]ax
45# ifdef CONFIG_X86_64
46 .mmu_write_cr3 = { 0x0f, 0x22, 0xdf }, // mov %rdi, %cr3
47 .irq_restore_fl = { 0x57, 0x9d }, // push %rdi; popfq
48 .cpu_wbinvd = { 0x0f, 0x09 }, // wbinvd
49 .cpu_usergs_sysret64 = { 0x0f, 0x01, 0xf8,
50 0x48, 0x0f, 0x07 }, // swapgs; sysretq
51 .cpu_swapgs = { 0x0f, 0x01, 0xf8 }, // swapgs
52 .mov64 = { 0x48, 0x89, 0xf8 }, // mov %rdi, %rax
53# else
54 .mmu_write_cr3 = { 0x0f, 0x22, 0xd8 }, // mov %eax, %cr3
55 .irq_restore_fl = { 0x50, 0x9d }, // push %eax; popf
56 .cpu_iret = { 0xcf }, // iret
57# endif
58};
59
60unsigned int paravirt_patch_ident_64(void *insn_buff, unsigned int len)
61{
62#ifdef CONFIG_X86_64
63 return PATCH(xxl, mov64, insn_buff, len);
64#endif
65 return 0;
66}
67# endif /* CONFIG_PARAVIRT_XXL */
68
69#ifdef CONFIG_PARAVIRT_SPINLOCKS
70struct patch_lock {
71 unsigned char queued_spin_unlock[3];
72 unsigned char vcpu_is_preempted[2];
73};
74
75static const struct patch_lock patch_data_lock = {
76 .vcpu_is_preempted = { 0x31, 0xc0 }, // xor %eax, %eax
77
78# ifdef CONFIG_X86_64
79 .queued_spin_unlock = { 0xc6, 0x07, 0x00 }, // movb $0, (%rdi)
80# else
81 .queued_spin_unlock = { 0xc6, 0x00, 0x00 }, // movb $0, (%eax)
82# endif
83};
84#endif /* CONFIG_PARAVIRT_SPINLOCKS */
85
86unsigned int native_patch(u8 type, void *insn_buff, unsigned long addr,
87 unsigned int len)
88{
89 switch (type) {
90
91#ifdef CONFIG_PARAVIRT_XXL
92 PATCH_CASE(irq, restore_fl, xxl, insn_buff, len);
93 PATCH_CASE(irq, save_fl, xxl, insn_buff, len);
94 PATCH_CASE(irq, irq_enable, xxl, insn_buff, len);
95 PATCH_CASE(irq, irq_disable, xxl, insn_buff, len);
96
97 PATCH_CASE(mmu, read_cr2, xxl, insn_buff, len);
98 PATCH_CASE(mmu, read_cr3, xxl, insn_buff, len);
99 PATCH_CASE(mmu, write_cr3, xxl, insn_buff, len);
100
101# ifdef CONFIG_X86_64
102 PATCH_CASE(cpu, usergs_sysret64, xxl, insn_buff, len);
103 PATCH_CASE(cpu, swapgs, xxl, insn_buff, len);
104 PATCH_CASE(cpu, wbinvd, xxl, insn_buff, len);
105# else
106 PATCH_CASE(cpu, iret, xxl, insn_buff, len);
107# endif
108#endif
109
110#ifdef CONFIG_PARAVIRT_SPINLOCKS
111 case PARAVIRT_PATCH(lock.queued_spin_unlock):
112 if (pv_is_native_spin_unlock())
113 return PATCH(lock, queued_spin_unlock, insn_buff, len);
114 break;
115
116 case PARAVIRT_PATCH(lock.vcpu_is_preempted):
117 if (pv_is_native_vcpu_is_preempted())
118 return PATCH(lock, vcpu_is_preempted, insn_buff, len);
119 break;
120#endif
121 default:
122 break;
123 }
124
125 return paravirt_patch_default(type, insn_buff, addr, len);
126}