[tip:x86/paravirt] x86/paravirt: Match paravirt patchlet field definition ordering to initialization ordering

[tip-bot for Ingo Molnar]

Commit-ID:  fc93dfd9345bb8b29a62b21cb0447dd1a3815f91
Gitweb:     https://git.kernel.org/tip/fc93dfd9345bb8b29a62b21cb0447dd1a3815f91
Author:     Ingo Molnar <mingo@xxxxxxxxxx>
AuthorDate: Thu, 25 Apr 2019 10:10:12 +0200
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Thu, 25 Apr 2019 12:00:44 +0200

x86/paravirt: Match paravirt patchlet field definition ordering to initialization ordering

Here's the objdump -D output of the PATCH_XXL data table:

0000000000000010 <patch_data_xxl>:
  10:   fa                      cli
  11:   fb                      sti
  12:   57                      push   %rdi
  13:   9d                      popfq
  14:   9c                      pushfq
  15:   58                      pop    %rax
  16:   0f 20 d0                mov    %cr2,%rax
  19:   0f 20 d8                mov    %cr3,%rax
  1c:   0f 22 df                mov    %rdi,%cr3
  1f:   0f 09                   wbinvd
  21:   0f 01 f8                swapgs
  24:   48 0f 07                sysretq
  27:   0f 01 f8                swapgs
  2a:   48 89 f8                mov    %rdi,%rax

Note how this doesn't match up to the source code:

static const struct patch_xxl patch_data_xxl = {
        .irq_irq_disable        = { 0xfa },             // cli
        .irq_irq_enable         = { 0xfb },             // sti
        .irq_save_fl            = { 0x9c, 0x58 },       // pushf; pop %[re]ax
        .mmu_read_cr2           = { 0x0f, 0x20, 0xd0 }, // mov %cr2, %[re]ax
        .mmu_read_cr3           = { 0x0f, 0x20, 0xd8 }, // mov %cr3, %[re]ax
        .irq_restore_fl         = { 0x57, 0x9d },       // push %rdi; popfq
        .mmu_write_cr3          = { 0x0f, 0x22, 0xdf }, // mov %rdi, %cr3
        .cpu_wbinvd             = { 0x0f, 0x09 },       // wbinvd
        .cpu_usergs_sysret64    = { 0x0f, 0x01, 0xf8,
                                    0x48, 0x0f, 0x07 }, // swapgs; sysretq
        .cpu_swapgs             = { 0x0f, 0x01, 0xf8 }, // swapgs
        .mov64                  = { 0x48, 0x89, 0xf8 }, // mov %rdi, %rax
        .irq_restore_fl         = { 0x50, 0x9d },       // push %eax; popf
        .mmu_write_cr3          = { 0x0f, 0x22, 0xd8 }, // mov %eax, %cr3
        .cpu_iret               = { 0xcf },             // iret
};

Note how they are reordered: in the generated code .irq_restore_fl comes
before .irq_save_fl, etc. This is because the field ordering in struct
patch_xxl does not match the initialization ordering of patch_data_xxl.

Match up the initialization order with the definition order - this makes
the disassembly easily reviewable:

0000000000000010 <patch_data_xxl>:
  10:   fa                      cli
  11:   fb                      sti
  12:   9c                      pushfq
  13:   58                      pop    %rax
  14:   0f 20 d0                mov    %cr2,%rax
  17:   0f 20 d8                mov    %cr3,%rax
  1a:   0f 22 df                mov    %rdi,%cr3
  1d:   57                      push   %rdi
  1e:   9d                      popfq
  1f:   0f 09                   wbinvd
  21:   0f 01 f8                swapgs
  24:   48 0f 07                sysretq
  27:   0f 01 f8                swapgs
  2a:   48 89 f8                mov    %rdi,%rax

Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Juergen Gross <jgross@xxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20190425081012.GA115378@xxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 arch/x86/kernel/paravirt_patch.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/paravirt_patch.c b/arch/x86/kernel/paravirt_patch.c
index 60e7a5e236c0..37b1d43d1e17 100644
--- a/arch/x86/kernel/paravirt_patch.c
+++ b/arch/x86/kernel/paravirt_patch.c
@@ -21,11 +21,11 @@
 struct patch_xxl {
 	const unsigned char	irq_irq_disable[1];
 	const unsigned char	irq_irq_enable[1];
-	const unsigned char	irq_restore_fl[2];
 	const unsigned char	irq_save_fl[2];
 	const unsigned char	mmu_read_cr2[3];
 	const unsigned char	mmu_read_cr3[3];
 	const unsigned char	mmu_write_cr3[3];
+	const unsigned char	irq_restore_fl[2];
 # ifdef CONFIG_X86_64
 	const unsigned char	cpu_wbinvd[2];
 	const unsigned char	cpu_usergs_sysret64[6];
@@ -43,16 +43,16 @@ static const struct patch_xxl patch_data_xxl = {
 	.mmu_read_cr2		= { 0x0f, 0x20, 0xd0 },	// mov %cr2, %[re]ax
 	.mmu_read_cr3		= { 0x0f, 0x20, 0xd8 },	// mov %cr3, %[re]ax
 # ifdef CONFIG_X86_64
-	.irq_restore_fl		= { 0x57, 0x9d },	// push %rdi; popfq
 	.mmu_write_cr3		= { 0x0f, 0x22, 0xdf },	// mov %rdi, %cr3
+	.irq_restore_fl		= { 0x57, 0x9d },	// push %rdi; popfq
 	.cpu_wbinvd		= { 0x0f, 0x09 },	// wbinvd
 	.cpu_usergs_sysret64	= { 0x0f, 0x01, 0xf8,
 				    0x48, 0x0f, 0x07 },	// swapgs; sysretq
 	.cpu_swapgs		= { 0x0f, 0x01, 0xf8 },	// swapgs
 	.mov64			= { 0x48, 0x89, 0xf8 },	// mov %rdi, %rax
 # else
-	.irq_restore_fl		= { 0x50, 0x9d },	// push %eax; popf
 	.mmu_write_cr3		= { 0x0f, 0x22, 0xd8 },	// mov %eax, %cr3
+	.irq_restore_fl		= { 0x50, 0x9d },	// push %eax; popf
 	.cpu_iret		= { 0xcf },		// iret
 # endif
 };