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Message-ID: <a1c4f192-f141-7488-ae6e-ad07101ba8da@suse.com>
Date: Wed, 25 Oct 2017 11:46:18 +0200
From: Juergen Gross <jgross@...e.com>
To: Josh Poimboeuf <jpoimboe@...hat.com>, x86@...nel.org
Cc: linux-kernel@...r.kernel.org, Andy Lutomirski <luto@...nel.org>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Sasha Levin <alexander.levin@...izon.com>,
live-patching@...r.kernel.org, Jiri Slaby <jslaby@...e.cz>,
Ingo Molnar <mingo@...nel.org>,
"H. Peter Anvin" <hpa@...or.com>,
Peter Zijlstra <peterz@...radead.org>,
Mike Galbraith <efault@....de>,
Chris Wright <chrisw@...s-sol.org>,
Alok Kataria <akataria@...are.com>,
Rusty Russell <rusty@...tcorp.com.au>,
virtualization@...ts.linux-foundation.org,
Boris Ostrovsky <boris.ostrovsky@...cle.com>,
xen-devel@...ts.xenproject.org,
Thomas Gleixner <tglx@...utronix.de>,
Borislav Petkov <bp@...en8.de>
Subject: Re: [PATCH 03/13] x86/paravirt: Convert native patch assembly code
strings to macros
On 04/10/17 17:58, Josh Poimboeuf wrote:
> Convert the hard-coded native patch assembly code strings to macros to
> facilitate sharing common code between 32-bit and 64-bit.
>
> These macros will also be used by a future patch which requires the GCC
> extended asm syntax of two '%' characters instead of one when specifying
> a register name.
>
> Signed-off-by: Josh Poimboeuf <jpoimboe@...hat.com>
Reviewed-by: Juergen Gross <jgross@...e.com>
Mind adding another patch to merge the now nearly identical
paravirt_patch_32.c and paravirt_patch_64.c either into paravirt.c
or paravirt_patch.c? This would require only very few #ifdef.
Juergen
> ---
> arch/x86/include/asm/special_insns.h | 24 ++++++++++++++++++++++++
> arch/x86/kernel/paravirt_patch_32.c | 21 +++++++++++----------
> arch/x86/kernel/paravirt_patch_64.c | 29 +++++++++++++++--------------
> 3 files changed, 50 insertions(+), 24 deletions(-)
>
> diff --git a/arch/x86/include/asm/special_insns.h b/arch/x86/include/asm/special_insns.h
> index ac402c6fc24b..0549c5f2c1b3 100644
> --- a/arch/x86/include/asm/special_insns.h
> +++ b/arch/x86/include/asm/special_insns.h
> @@ -6,6 +6,30 @@
>
> #include <asm/nops.h>
>
> +#ifdef CONFIG_X86_64
> +# define _REG_ARG1 "%rdi"
> +# define NATIVE_IDENTITY_32 "mov %edi, %eax"
> +# define NATIVE_USERGS_SYSRET64 "swapgs; sysretq"
> +#else
> +# define _REG_ARG1 "%eax"
> +#endif
> +
> +#define _REG_RET "%" _ASM_AX
> +
> +#define NATIVE_ZERO "xor " _REG_ARG1 ", " _REG_ARG1
> +#define NATIVE_IDENTITY "mov " _REG_ARG1 ", " _REG_RET
> +#define NATIVE_SAVE_FL "pushf; pop " _REG_RET
> +#define NATIVE_RESTORE_FL "push " _REG_ARG1 "; popf"
> +#define NATIVE_IRQ_DISABLE "cli"
> +#define NATIVE_IRQ_ENABLE "sti"
> +#define NATIVE_READ_CR2 "mov %cr2, " _REG_RET
> +#define NATIVE_READ_CR3 "mov %cr3, " _REG_RET
> +#define NATIVE_WRITE_CR3 "mov " _REG_ARG1 ", %cr3"
> +#define NATIVE_FLUSH_TLB_SINGLE "invlpg (" _REG_ARG1 ")"
> +#define NATIVE_SWAPGS "swapgs"
> +#define NATIVE_IRET "iret"
> +#define NATIVE_QUEUED_SPIN_UNLOCK "movb $0, (" _REG_ARG1 ")"
> +
> /*
> * Volatile isn't enough to prevent the compiler from reordering the
> * read/write functions for the control registers and messing everything up.
> diff --git a/arch/x86/kernel/paravirt_patch_32.c b/arch/x86/kernel/paravirt_patch_32.c
> index 553acbbb4d32..c9c6106ae714 100644
> --- a/arch/x86/kernel/paravirt_patch_32.c
> +++ b/arch/x86/kernel/paravirt_patch_32.c
> @@ -1,17 +1,18 @@
> #include <asm/paravirt.h>
> +#include <asm/special_insns.h>
>
> -DEF_NATIVE(pv_irq_ops, irq_disable, "cli");
> -DEF_NATIVE(pv_irq_ops, irq_enable, "sti");
> -DEF_NATIVE(pv_irq_ops, restore_fl, "push %eax; popf");
> -DEF_NATIVE(pv_irq_ops, save_fl, "pushf; pop %eax");
> -DEF_NATIVE(pv_cpu_ops, iret, "iret");
> -DEF_NATIVE(pv_mmu_ops, read_cr2, "mov %cr2, %eax");
> -DEF_NATIVE(pv_mmu_ops, write_cr3, "mov %eax, %cr3");
> -DEF_NATIVE(pv_mmu_ops, read_cr3, "mov %cr3, %eax");
> +DEF_NATIVE(pv_irq_ops, save_fl, NATIVE_SAVE_FL);
> +DEF_NATIVE(pv_irq_ops, restore_fl, NATIVE_RESTORE_FL);
> +DEF_NATIVE(pv_irq_ops, irq_disable, NATIVE_IRQ_DISABLE);
> +DEF_NATIVE(pv_irq_ops, irq_enable, NATIVE_IRQ_ENABLE);
> +DEF_NATIVE(pv_cpu_ops, iret, NATIVE_IRET);
> +DEF_NATIVE(pv_mmu_ops, read_cr2, NATIVE_READ_CR2);
> +DEF_NATIVE(pv_mmu_ops, read_cr3, NATIVE_READ_CR3);
> +DEF_NATIVE(pv_mmu_ops, write_cr3, NATIVE_WRITE_CR3);
>
> #if defined(CONFIG_PARAVIRT_SPINLOCKS)
> -DEF_NATIVE(pv_lock_ops, queued_spin_unlock, "movb $0, (%eax)");
> -DEF_NATIVE(pv_lock_ops, vcpu_is_preempted, "xor %eax, %eax");
> +DEF_NATIVE(pv_lock_ops, queued_spin_unlock, NATIVE_QUEUED_SPIN_UNLOCK);
> +DEF_NATIVE(pv_lock_ops, vcpu_is_preempted, NATIVE_ZERO);
> #endif
>
> unsigned paravirt_patch_ident_32(void *insnbuf, unsigned len)
> diff --git a/arch/x86/kernel/paravirt_patch_64.c b/arch/x86/kernel/paravirt_patch_64.c
> index 0a1ba3f80cbf..0aa232edd670 100644
> --- a/arch/x86/kernel/paravirt_patch_64.c
> +++ b/arch/x86/kernel/paravirt_patch_64.c
> @@ -1,25 +1,26 @@
> #include <asm/paravirt.h>
> #include <asm/asm-offsets.h>
> +#include <asm/special_insns.h>
> #include <linux/stringify.h>
>
> -DEF_NATIVE(pv_irq_ops, irq_disable, "cli");
> -DEF_NATIVE(pv_irq_ops, irq_enable, "sti");
> -DEF_NATIVE(pv_irq_ops, restore_fl, "pushq %rdi; popfq");
> -DEF_NATIVE(pv_irq_ops, save_fl, "pushfq; popq %rax");
> -DEF_NATIVE(pv_mmu_ops, read_cr2, "movq %cr2, %rax");
> -DEF_NATIVE(pv_mmu_ops, read_cr3, "movq %cr3, %rax");
> -DEF_NATIVE(pv_mmu_ops, write_cr3, "movq %rdi, %cr3");
> -DEF_NATIVE(pv_mmu_ops, flush_tlb_single, "invlpg (%rdi)");
> +DEF_NATIVE(pv_irq_ops, save_fl, NATIVE_SAVE_FL);
> +DEF_NATIVE(pv_irq_ops, restore_fl, NATIVE_RESTORE_FL);
> +DEF_NATIVE(pv_irq_ops, irq_disable, NATIVE_IRQ_DISABLE);
> +DEF_NATIVE(pv_irq_ops, irq_enable, NATIVE_IRQ_ENABLE);
> +DEF_NATIVE(pv_mmu_ops, read_cr2, NATIVE_READ_CR2);
> +DEF_NATIVE(pv_mmu_ops, read_cr3, NATIVE_READ_CR3);
> +DEF_NATIVE(pv_mmu_ops, write_cr3, NATIVE_WRITE_CR3);
> +DEF_NATIVE(pv_mmu_ops, flush_tlb_single, NATIVE_FLUSH_TLB_SINGLE);
>
> -DEF_NATIVE(pv_cpu_ops, usergs_sysret64, "swapgs; sysretq");
> -DEF_NATIVE(pv_cpu_ops, swapgs, "swapgs");
> +DEF_NATIVE(pv_cpu_ops, usergs_sysret64, NATIVE_USERGS_SYSRET64);
> +DEF_NATIVE(pv_cpu_ops, swapgs, NATIVE_SWAPGS);
>
> -DEF_NATIVE(, mov32, "mov %edi, %eax");
> -DEF_NATIVE(, mov64, "mov %rdi, %rax");
> +DEF_NATIVE(, mov32, NATIVE_IDENTITY_32);
> +DEF_NATIVE(, mov64, NATIVE_IDENTITY);
>
> #if defined(CONFIG_PARAVIRT_SPINLOCKS)
> -DEF_NATIVE(pv_lock_ops, queued_spin_unlock, "movb $0, (%rdi)");
> -DEF_NATIVE(pv_lock_ops, vcpu_is_preempted, "xor %rax, %rax");
> +DEF_NATIVE(pv_lock_ops, queued_spin_unlock, NATIVE_QUEUED_SPIN_UNLOCK);
> +DEF_NATIVE(pv_lock_ops, vcpu_is_preempted, NATIVE_ZERO);
> #endif
>
> unsigned paravirt_patch_ident_32(void *insnbuf, unsigned len)
>
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