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 <jniet...@gmail.com>
> ---
> 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 < &bpts[NBPTS]; ++bp) {
> if (!bp->enabled && atomic_read(&bp->ref_count) == 0) {
> bp->address = a;
> - bp->instr[1] = bpinstr;
> - store_inst(&bp->instr[1]);
> + patch_instruction(&bp->instr[1], bpinstr);
> return bp;
> }
> }
> @@ -913,7 +907,7 @@ static void insert_bpts(void)
> bp->enabled = 0;
> continue;
> }
> - store_inst(&bp->instr[0]);
> + patch_instruction(&bp->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
