Re: [PATCH v3 08/14] powerpc/xmon: Remove store_inst() for patch_instruction()
On Wed, Feb 26, 2020 at 6:04 PM Nicholas Piggin wrote:
>
> Jordan Niethe's on February 26, 2020 2:07 pm:
> > For modifying instructions in xmon, patch_instruction() can serve the
> > same role that store_inst() is performing with the advantage of not
> > being specific to xmon. In some places patch_instruction() is already
> > being using followed by store_inst(). In these cases just remove the
> > store_inst(). Otherwise replace store_inst() with patch_instruction().
> >
> > Signed-off-by: Jordan Niethe
> > ---
> > arch/powerpc/xmon/xmon.c | 13 ++---
> > 1 file changed, 2 insertions(+), 11 deletions(-)
> >
> > diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
> > index 897e512c6379..a673cf55641c 100644
> > --- a/arch/powerpc/xmon/xmon.c
> > +++ b/arch/powerpc/xmon/xmon.c
> > @@ -325,11 +325,6 @@ static inline void sync(void)
> > asm volatile("sync; isync");
> > }
> >
> > -static inline void store_inst(void *p)
> > -{
> > - asm volatile ("dcbst 0,%0; sync; icbi 0,%0; isync" : : "r" (p));
> > -}
> > -
> > static inline void cflush(void *p)
> > {
> > asm volatile ("dcbf 0,%0; icbi 0,%0" : : "r" (p));
> > @@ -882,8 +877,7 @@ static struct bpt *new_breakpoint(unsigned long a)
> > for (bp = bpts; bp < [NBPTS]; ++bp) {
> > if (!bp->enabled && atomic_read(>ref_count) == 0) {
> > bp->address = a;
> > - bp->instr[1] = bpinstr;
> > - store_inst(>instr[1]);
> > + patch_instruction(>instr[1], bpinstr);
> > return bp;
> > }
> > }
> > @@ -913,7 +907,7 @@ static void insert_bpts(void)
> > bp->enabled = 0;
> > continue;
> > }
> > - store_inst(>instr[0]);
> > + patch_instruction(>instr[0], bp->instr[0]);
>
> Hmm that's a bit weird. Can you read instructions into a local variable
> first, do the checks on them, then patch them into their execution
> location?
I agree it is weird, local variables would be better.
>
> Otherwise, good cleanup.
>
> Thanks,
> Nick
Re: [PATCH v3 08/14] powerpc/xmon: Remove store_inst() for patch_instruction()
Jordan Niethe's on February 26, 2020 2:07 pm:
> For modifying instructions in xmon, patch_instruction() can serve the
> same role that store_inst() is performing with the advantage of not
> being specific to xmon. In some places patch_instruction() is already
> being using followed by store_inst(). In these cases just remove the
> store_inst(). Otherwise replace store_inst() with patch_instruction().
>
> Signed-off-by: Jordan Niethe
> ---
> arch/powerpc/xmon/xmon.c | 13 ++---
> 1 file changed, 2 insertions(+), 11 deletions(-)
>
> diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
> index 897e512c6379..a673cf55641c 100644
> --- a/arch/powerpc/xmon/xmon.c
> +++ b/arch/powerpc/xmon/xmon.c
> @@ -325,11 +325,6 @@ static inline void sync(void)
> asm volatile("sync; isync");
> }
>
> -static inline void store_inst(void *p)
> -{
> - asm volatile ("dcbst 0,%0; sync; icbi 0,%0; isync" : : "r" (p));
> -}
> -
> static inline void cflush(void *p)
> {
> asm volatile ("dcbf 0,%0; icbi 0,%0" : : "r" (p));
> @@ -882,8 +877,7 @@ static struct bpt *new_breakpoint(unsigned long a)
> for (bp = bpts; bp < [NBPTS]; ++bp) {
> if (!bp->enabled && atomic_read(>ref_count) == 0) {
> bp->address = a;
> - bp->instr[1] = bpinstr;
> - store_inst(>instr[1]);
> + patch_instruction(>instr[1], bpinstr);
> return bp;
> }
> }
> @@ -913,7 +907,7 @@ static void insert_bpts(void)
> bp->enabled = 0;
> continue;
> }
> - store_inst(>instr[0]);
> + patch_instruction(>instr[0], bp->instr[0]);
Hmm that's a bit weird. Can you read instructions into a local variable
first, do the checks on them, then patch them into their execution
location?
Otherwise, good cleanup.
Thanks,
Nick
[PATCH v3 08/14] powerpc/xmon: Remove store_inst() for patch_instruction()
For modifying instructions in xmon, patch_instruction() can serve the
same role that store_inst() is performing with the advantage of not
being specific to xmon. In some places patch_instruction() is already
being using followed by store_inst(). In these cases just remove the
store_inst(). Otherwise replace store_inst() with patch_instruction().
Signed-off-by: Jordan Niethe
---
arch/powerpc/xmon/xmon.c | 13 ++---
1 file changed, 2 insertions(+), 11 deletions(-)
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index 897e512c6379..a673cf55641c 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -325,11 +325,6 @@ static inline void sync(void)
asm volatile("sync; isync");
}
-static inline void store_inst(void *p)
-{
- asm volatile ("dcbst 0,%0; sync; icbi 0,%0; isync" : : "r" (p));
-}
-
static inline void cflush(void *p)
{
asm volatile ("dcbf 0,%0; icbi 0,%0" : : "r" (p));
@@ -882,8 +877,7 @@ static struct bpt *new_breakpoint(unsigned long a)
for (bp = bpts; bp < [NBPTS]; ++bp) {
if (!bp->enabled && atomic_read(>ref_count) == 0) {
bp->address = a;
- bp->instr[1] = bpinstr;
- store_inst(>instr[1]);
+ patch_instruction(>instr[1], bpinstr);
return bp;
}
}
@@ -913,7 +907,7 @@ static void insert_bpts(void)
bp->enabled = 0;
continue;
}
- store_inst(>instr[0]);
+ patch_instruction(>instr[0], bp->instr[0]);
if (bp->enabled & BP_CIABR)
continue;
if (patch_instruction((unsigned int *)bp->address,
@@ -923,7 +917,6 @@ static void insert_bpts(void)
bp->enabled &= ~BP_TRAP;
continue;
}
- store_inst((void *)bp->address);
}
}
@@ -958,8 +951,6 @@ static void remove_bpts(void)
(unsigned int *)bp->address, bp->instr[0]) != 0)
printf("Couldn't remove breakpoint at %lx\n",
bp->address);
- else
- store_inst((void *)bp->address);
}
}
--
2.17.1
