* [PATCH] powerpc/tm: Clean up duplication of code
@ 2016-05-11 4:55 Rashmica Gupta
2016-05-11 5:03 ` Balbir Singh
0 siblings, 1 reply; 4+ messages in thread
From: Rashmica Gupta @ 2016-05-11 4:55 UTC (permalink / raw)
To: mpe; +Cc: linuxppc-dev
The same logic for tm_abort appears twice, so pull it out into a
function.
Signed-off-by: Rashmica Gupta <rashmicy@gmail.com>
---
arch/powerpc/mm/hash_utils_64.c | 47 ++++++++++++++++++-----------------------
1 file changed, 21 insertions(+), 26 deletions(-)
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 7635b1c6b5da..1cef8f5aee9b 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -1318,6 +1318,25 @@ out_exit:
local_irq_restore(flags);
}
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+ /* Transactions are not aborted by tlbiel, only tlbie.
+ * Without, syncing a page back to a block device w/ PIO could pick up
+ * transactional data (bad!) so we force an abort here. Before the
+ * sync the page will be made read-only, which will flush_hash_page.
+ * BIG ISSUE here: if the kernel uses a page from userspace without
+ * unmapping it first, it may see the speculated version.
+ */
+static inline void abort_tm(int local)
+{
+ if (local && cpu_has_feature(CPU_FTR_TM) &&
+ current->thread.regs &&
+ MSR_TM_ACTIVE(current->thread.regs->msr)) {
+ tm_enable();
+ tm_abort(TM_CAUSE_TLBI);
+ }
+}
+#endif
+
/* WARNING: This is called from hash_low_64.S, if you change this prototype,
* do not forget to update the assembly call site !
*/
@@ -1344,19 +1363,7 @@ void flush_hash_page(unsigned long vpn, real_pte_t pte, int psize, int ssize,
} pte_iterate_hashed_end();
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
- /* Transactions are not aborted by tlbiel, only tlbie.
- * Without, syncing a page back to a block device w/ PIO could pick up
- * transactional data (bad!) so we force an abort here. Before the
- * sync the page will be made read-only, which will flush_hash_page.
- * BIG ISSUE here: if the kernel uses a page from userspace without
- * unmapping it first, it may see the speculated version.
- */
- if (local && cpu_has_feature(CPU_FTR_TM) &&
- current->thread.regs &&
- MSR_TM_ACTIVE(current->thread.regs->msr)) {
- tm_enable();
- tm_abort(TM_CAUSE_TLBI);
- }
+ abort_tm(local);
#endif
}
@@ -1415,19 +1422,7 @@ void flush_hash_hugepage(unsigned long vsid, unsigned long addr,
}
tm_abort:
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
- /* Transactions are not aborted by tlbiel, only tlbie.
- * Without, syncing a page back to a block device w/ PIO could pick up
- * transactional data (bad!) so we force an abort here. Before the
- * sync the page will be made read-only, which will flush_hash_page.
- * BIG ISSUE here: if the kernel uses a page from userspace without
- * unmapping it first, it may see the speculated version.
- */
- if (local && cpu_has_feature(CPU_FTR_TM) &&
- current->thread.regs &&
- MSR_TM_ACTIVE(current->thread.regs->msr)) {
- tm_enable();
- tm_abort(TM_CAUSE_TLBI);
- }
+ abort_tm(local);
#endif
return;
}
--
2.5.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] powerpc/tm: Clean up duplication of code
2016-05-11 4:55 [PATCH] powerpc/tm: Clean up duplication of code Rashmica Gupta
@ 2016-05-11 5:03 ` Balbir Singh
2016-05-11 7:44 ` Rashmica
0 siblings, 1 reply; 4+ messages in thread
From: Balbir Singh @ 2016-05-11 5:03 UTC (permalink / raw)
To: linuxppc-dev, Rashmica Gupta
On 11/05/16 14:55, Rashmica Gupta wrote:
> The same logic for tm_abort appears twice, so pull it out into a
> function.
>
> Signed-off-by: Rashmica Gupta <rashmicy@gmail.com>
> ---
> arch/powerpc/mm/hash_utils_64.c | 47 ++++++++++++++++++-----------------------
> 1 file changed, 21 insertions(+), 26 deletions(-)
>
> diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
> index 7635b1c6b5da..1cef8f5aee9b 100644
> --- a/arch/powerpc/mm/hash_utils_64.c
> +++ b/arch/powerpc/mm/hash_utils_64.c
> @@ -1318,6 +1318,25 @@ out_exit:
> local_irq_restore(flags);
> }
>
> +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
> + /* Transactions are not aborted by tlbiel, only tlbie.
> + * Without, syncing a page back to a block device w/ PIO could pick up
> + * transactional data (bad!) so we force an abort here. Before the
> + * sync the page will be made read-only, which will flush_hash_page.
> + * BIG ISSUE here: if the kernel uses a page from userspace without
> + * unmapping it first, it may see the speculated version.
> + */
> +static inline void abort_tm(int local)
> +{
> + if (local && cpu_has_feature(CPU_FTR_TM) &&
> + current->thread.regs &&
> + MSR_TM_ACTIVE(current->thread.regs->msr)) {
> + tm_enable();
> + tm_abort(TM_CAUSE_TLBI);
> + }
> +}
While your at this do
#else
static inline void abort_tm(int local)
{
}
> +#endif
> +
> /* WARNING: This is called from hash_low_64.S, if you change this prototype,
> * do not forget to update the assembly call site !
> */
> @@ -1344,19 +1363,7 @@ void flush_hash_page(unsigned long vpn, real_pte_t pte, int psize, int ssize,
> } pte_iterate_hashed_end();
>
> #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
Then remove these extra #ifdef
> - /* Transactions are not aborted by tlbiel, only tlbie.
> - * Without, syncing a page back to a block device w/ PIO could pick up
> - * transactional data (bad!) so we force an abort here. Before the
> - * sync the page will be made read-only, which will flush_hash_page.
> - * BIG ISSUE here: if the kernel uses a page from userspace without
> - * unmapping it first, it may see the speculated version.
> - */
> - if (local && cpu_has_feature(CPU_FTR_TM) &&
> - current->thread.regs &&
> - MSR_TM_ACTIVE(current->thread.regs->msr)) {
> - tm_enable();
> - tm_abort(TM_CAUSE_TLBI);
> - }
> + abort_tm(local);
> #endif
> }
>
> @@ -1415,19 +1422,7 @@ void flush_hash_hugepage(unsigned long vsid, unsigned long addr,
> }
> tm_abort:
> #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
Then remove these extra #ifdef
> - /* Transactions are not aborted by tlbiel, only tlbie.
> - * Without, syncing a page back to a block device w/ PIO could pick up
> - * transactional data (bad!) so we force an abort here. Before the
> - * sync the page will be made read-only, which will flush_hash_page.
> - * BIG ISSUE here: if the kernel uses a page from userspace without
> - * unmapping it first, it may see the speculated version.
> - */
> - if (local && cpu_has_feature(CPU_FTR_TM) &&
> - current->thread.regs &&
> - MSR_TM_ACTIVE(current->thread.regs->msr)) {
> - tm_enable();
> - tm_abort(TM_CAUSE_TLBI);
> - }
> + abort_tm(local);
> #endif
> return;
> }
>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] powerpc/tm: Clean up duplication of code
2016-05-11 5:03 ` Balbir Singh
@ 2016-05-11 7:44 ` Rashmica
2016-05-11 11:12 ` Michael Ellerman
0 siblings, 1 reply; 4+ messages in thread
From: Rashmica @ 2016-05-11 7:44 UTC (permalink / raw)
To: Balbir Singh, linuxppc-dev
On 11/05/16 15:03, Balbir Singh wrote:
>
> On 11/05/16 14:55, Rashmica Gupta wrote:
>> The same logic for tm_abort appears twice, so pull it out into a
>> function.
>>
>> Signed-off-by: Rashmica Gupta <rashmicy@gmail.com>
>> ---
>> arch/powerpc/mm/hash_utils_64.c | 47 ++++++++++++++++++-----------------------
>> 1 file changed, 21 insertions(+), 26 deletions(-)
>>
>> diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
>> index 7635b1c6b5da..1cef8f5aee9b 100644
>> --- a/arch/powerpc/mm/hash_utils_64.c
>> +++ b/arch/powerpc/mm/hash_utils_64.c
>> @@ -1318,6 +1318,25 @@ out_exit:
>> local_irq_restore(flags);
>> }
>>
>> +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
>> + /* Transactions are not aborted by tlbiel, only tlbie.
>> + * Without, syncing a page back to a block device w/ PIO could pick up
>> + * transactional data (bad!) so we force an abort here. Before the
>> + * sync the page will be made read-only, which will flush_hash_page.
>> + * BIG ISSUE here: if the kernel uses a page from userspace without
>> + * unmapping it first, it may see the speculated version.
>> + */
>> +static inline void abort_tm(int local)
>> +{
>> + if (local && cpu_has_feature(CPU_FTR_TM) &&
>> + current->thread.regs &&
>> + MSR_TM_ACTIVE(current->thread.regs->msr)) {
>> + tm_enable();
>> + tm_abort(TM_CAUSE_TLBI);
>> + }
>> +}
> While your at this do
>
> #else
>
> static inline void abort_tm(int local)
> {
> }
If I'm doing that, wouldn't it make more sense to write:
+static inline void abort_tm(int local)
+{
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+ if (local && cpu_has_feature(CPU_FTR_TM) &&
+ current->thread.regs &&
+ MSR_TM_ACTIVE(current->thread.regs->msr)) {
+ tm_enable();
+ tm_abort(TM_CAUSE_TLBI);
+ }
+#endif
+}
>> +#endif
>> +
>> /* WARNING: This is called from hash_low_64.S, if you change this prototype,
>> * do not forget to update the assembly call site !
>> */
>> @@ -1344,19 +1363,7 @@ void flush_hash_page(unsigned long vpn, real_pte_t pte, int psize, int ssize,
>> } pte_iterate_hashed_end();
>>
>> #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
> Then remove these extra #ifdef
>> - /* Transactions are not aborted by tlbiel, only tlbie.
>> - * Without, syncing a page back to a block device w/ PIO could pick up
>> - * transactional data (bad!) so we force an abort here. Before the
>> - * sync the page will be made read-only, which will flush_hash_page.
>> - * BIG ISSUE here: if the kernel uses a page from userspace without
>> - * unmapping it first, it may see the speculated version.
>> - */
>> - if (local && cpu_has_feature(CPU_FTR_TM) &&
>> - current->thread.regs &&
>> - MSR_TM_ACTIVE(current->thread.regs->msr)) {
>> - tm_enable();
>> - tm_abort(TM_CAUSE_TLBI);
>> - }
>> + abort_tm(local);
>> #endif
>> }
>>
>> @@ -1415,19 +1422,7 @@ void flush_hash_hugepage(unsigned long vsid, unsigned long addr,
>> }
>> tm_abort:
>> #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
> Then remove these extra #ifdef
>> - /* Transactions are not aborted by tlbiel, only tlbie.
>> - * Without, syncing a page back to a block device w/ PIO could pick up
>> - * transactional data (bad!) so we force an abort here. Before the
>> - * sync the page will be made read-only, which will flush_hash_page.
>> - * BIG ISSUE here: if the kernel uses a page from userspace without
>> - * unmapping it first, it may see the speculated version.
>> - */
>> - if (local && cpu_has_feature(CPU_FTR_TM) &&
>> - current->thread.regs &&
>> - MSR_TM_ACTIVE(current->thread.regs->msr)) {
>> - tm_enable();
>> - tm_abort(TM_CAUSE_TLBI);
>> - }
>> + abort_tm(local);
>> #endif
>> return;
>> }
>>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] powerpc/tm: Clean up duplication of code
2016-05-11 7:44 ` Rashmica
@ 2016-05-11 11:12 ` Michael Ellerman
0 siblings, 0 replies; 4+ messages in thread
From: Michael Ellerman @ 2016-05-11 11:12 UTC (permalink / raw)
To: Rashmica, Balbir Singh, linuxppc-dev
On Wed, 2016-05-11 at 17:44 +1000, Rashmica wrote:
> On 11/05/16 15:03, Balbir Singh wrote:
> > On 11/05/16 14:55, Rashmica Gupta wrote:
> > > The same logic for tm_abort appears twice, so pull it out into a
> > > function.
> > >
> > > diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
> > > index 7635b1c6b5da..1cef8f5aee9b 100644
> > > --- a/arch/powerpc/mm/hash_utils_64.c
> > > +++ b/arch/powerpc/mm/hash_utils_64.c
> > > @@ -1318,6 +1318,25 @@ out_exit:
> > > local_irq_restore(flags);
> > > }
> > >
> > > +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
> > > + /* Transactions are not aborted by tlbiel, only tlbie.
Can you fix up the comment formatting while you're there, should be:
/*
* Transactions are not aborted by tlbiel, only tlbie.
> > > + * Without, syncing a page back to a block device w/ PIO could pick up
> > > + * transactional data (bad!) so we force an abort here. Before the
> > > + * sync the page will be made read-only, which will flush_hash_page.
> > > + * BIG ISSUE here: if the kernel uses a page from userspace without
> > > + * unmapping it first, it may see the speculated version.
> > > + */
> > > +static inline void abort_tm(int local)
> > > +{
> > > + if (local && cpu_has_feature(CPU_FTR_TM) &&
> > > + current->thread.regs &&
> > > + MSR_TM_ACTIVE(current->thread.regs->msr)) {
> > > + tm_enable();
> > > + tm_abort(TM_CAUSE_TLBI);
> > > + }
> > > +}
> > While your at this do
> >
> > #else
> >
> > static inline void abort_tm(int local)
> > {
> > }
> If I'm doing that, wouldn't it make more sense to write:
>
> +static inline void abort_tm(int local)
It needs a better name. Perhaps tlb_flush_abort_tm() ?
> +{
> +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
> + if (local && cpu_has_feature(CPU_FTR_TM) &&
> + current->thread.regs &&
> + MSR_TM_ACTIVE(current->thread.regs->msr)) {
> + tm_enable();
> + tm_abort(TM_CAUSE_TLBI);
> + }
> +#endif
> +}
In this case it would make some sense.
But the goal is "no #ifdef's in C code", which that would violate.
And if you have two functions that need to be inside the #ifdef then the above
doesn't work anymore.
So the preferred style is:
#ifdef CONFIG_FOO
static void foo(int bar)
{
...
}
#else /* !CONFIG_FOO */
static inline foo(int bar) { }
#endif
And when it expands you end up with:
#ifdef CONFIG_FOO
static void foo(int bar)
{
...
}
static void foo_new(int bar)
{
...
}
#else /* !CONFIG_FOO */
static inline foo(int bar) { }
static inline foo_new(int bar) { }
#endif
cheers
^ permalink raw reply [flat|nested] 4+ messages in thread
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2016-05-11 4:55 [PATCH] powerpc/tm: Clean up duplication of code Rashmica Gupta
2016-05-11 5:03 ` Balbir Singh
2016-05-11 7:44 ` Rashmica
2016-05-11 11:12 ` Michael Ellerman
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