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SubjectRe: [PATCH v2] x86/paravirt: Get rid of patch_site and patch_default labels
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On 07/09/18 22:10, Borislav Petkov wrote:
> On Fri, Sep 07, 2018 at 12:51:12PM +0200, Borislav Petkov wrote:
>> Whoops, no, it is still being used. Lemme see if I can remove all the
>> labels in that function.
>
> Ok, I think I've gotten rid of them all, in both 32- and 64-bit
> versions. It boots here and a bunch of all*config builds pass.
>
> ---
> From: Borislav Petkov <bp@suse.de>
> Date: Fri, 7 Sep 2018 12:47:10 +0200
> MIME-Version: 1.0
> Content-Type: text/plain; charset=UTF-8
> Content-Transfer-Encoding: 8bit
>
> When CONFIG_PARAVIRT_SPINLOCKS=n, it fires
>
> arch/x86/kernel/paravirt_patch_64.c: In function ‘native_patch’:
> arch/x86/kernel/paravirt_patch_64.c:89:1: warning: label ‘patch_site’ defined but not used [-Wunused-label]
> patch_site:
>
> but those labels can simply be removed by directly calling the
> respective functions there.
>
> Signed-off-by: Borislav Petkov <bp@suse.de>
> Cc: Juergen Gross <jgross@suse.com>
> Cc: x86@kernel.org
> Cc: virtualization@lists.linux-foundation.org
> ---
> arch/x86/kernel/paravirt_patch_32.c | 21 ++++++++++-----------
> arch/x86/kernel/paravirt_patch_64.c | 20 +++++++++-----------
> 2 files changed, 19 insertions(+), 22 deletions(-)
>
> diff --git a/arch/x86/kernel/paravirt_patch_32.c b/arch/x86/kernel/paravirt_patch_32.c
> index d460cbcabcfe..af57f0d0789f 100644
> --- a/arch/x86/kernel/paravirt_patch_32.c
> +++ b/arch/x86/kernel/paravirt_patch_32.c
> @@ -34,14 +34,16 @@ extern bool pv_is_native_vcpu_is_preempted(void);
>
> unsigned native_patch(u8 type, void *ibuf, unsigned long addr, unsigned len)
> {
> - const unsigned char *start, *end;
> + const unsigned char *start __maybe_unused, *end __maybe_unused;
> unsigned ret;
>
> #define PATCH_SITE(ops, x) \
> case PARAVIRT_PATCH(ops.x): \
> start = start_##ops##_##x; \
> end = end_##ops##_##x; \
> - goto patch_site
> + \
> + return paravirt_patch_insns(ibuf, len, start, end);
> +
> switch (type) {
> #ifdef CONFIG_PARAVIRT_XXL
> PATCH_SITE(irq, irq_disable);
> @@ -58,27 +60,24 @@ unsigned native_patch(u8 type, void *ibuf, unsigned long addr, unsigned len)
> if (pv_is_native_spin_unlock()) {
> start = start_lock_queued_spin_unlock;
> end = end_lock_queued_spin_unlock;
> - goto patch_site;
> +
> + return paravirt_patch_insns(ibuf, len, start, end);
> }
> - goto patch_default;
> + return paravirt_patch_default(type, ibuf, addr, len);
>
> case PARAVIRT_PATCH(lock.vcpu_is_preempted):
> if (pv_is_native_vcpu_is_preempted()) {
> start = start_lock_vcpu_is_preempted;
> end = end_lock_vcpu_is_preempted;
> - goto patch_site;
> +
> + return paravirt_patch_insns(ibuf, len, start, end);
> }
> - goto patch_default;
> + return paravirt_patch_default(type, ibuf, addr, len);
> #endif
>
> default:
> -patch_default: __maybe_unused
> ret = paravirt_patch_default(type, ibuf, addr, len);
> break;
> -
> -patch_site:
> - ret = paravirt_patch_insns(ibuf, len, start, end);
> - break;
> }
> #undef PATCH_SITE
> return ret;
> diff --git a/arch/x86/kernel/paravirt_patch_64.c b/arch/x86/kernel/paravirt_patch_64.c
> index 5ad5bcda9dc6..2db6c615932f 100644
> --- a/arch/x86/kernel/paravirt_patch_64.c
> +++ b/arch/x86/kernel/paravirt_patch_64.c
> @@ -42,14 +42,15 @@ extern bool pv_is_native_vcpu_is_preempted(void);
>
> unsigned native_patch(u8 type, void *ibuf, unsigned long addr, unsigned len)
> {
> - const unsigned char *start, *end;
> + const unsigned char *start __maybe_unused, *end __maybe_unused;

Drop start and end and ...

> unsigned ret;
>
> #define PATCH_SITE(ops, x) \
> case PARAVIRT_PATCH(ops.x): \
> start = start_##ops##_##x; \
> end = end_##ops##_##x; \
> - goto patch_site
> + \
> + return paravirt_patch_insns(ibuf, len, start, end);

... do: return paravirt_patch_insns(ibuf, len, start_##ops##_##x,
end_##ops##_##x)

and please omit the semicolon after the last instruction in the macro.

(below the same)

> switch(type) {
> #ifdef CONFIG_PARAVIRT_XXL
> PATCH_SITE(irq, restore_fl);
> @@ -68,27 +69,24 @@ unsigned native_patch(u8 type, void *ibuf, unsigned long addr, unsigned len)
> if (pv_is_native_spin_unlock()) {
> start = start_lock_queued_spin_unlock;
> end = end_lock_queued_spin_unlock;
> - goto patch_site;
> +
> + return paravirt_patch_insns(ibuf, len, start, end);
> }
> - goto patch_default;
> + return paravirt_patch_default(type, ibuf, addr, len);
>
> case PARAVIRT_PATCH(lock.vcpu_is_preempted):
> if (pv_is_native_vcpu_is_preempted()) {
> start = start_lock_vcpu_is_preempted;
> end = end_lock_vcpu_is_preempted;
> - goto patch_site;
> +
> + return paravirt_patch_insns(ibuf, len, start, end);
> }
> - goto patch_default;
> + return paravirt_patch_default(type, ibuf, addr, len);
> #endif
>
> default:
> -patch_default: __maybe_unused
> ret = paravirt_patch_default(type, ibuf, addr, len);
> break;
> -
> -patch_site:
> - ret = paravirt_patch_insns(ibuf, len, start, end);
> - break;
> }
> #undef PATCH_SITE
> return ret;
>

Juergen

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