[PATCH v5 18/21] powerpc64: Add prefixed instructions to instruction data type
Alistair Popple
alistair at popple.id.au
Tue Apr 7 11:39:17 AEST 2020
On Monday, 6 April 2020 8:42:57 PM AEST Jordan Niethe wrote:
> On Mon, 6 Apr 2020, 7:52 pm Alistair Popple, <alistair at popple.id.au> wrote:
> > > diff --git a/arch/powerpc/include/asm/inst.h
> > > b/arch/powerpc/include/asm/inst.h index 70b37a35a91a..7e23e7146c66
> > > 100644
> > > --- a/arch/powerpc/include/asm/inst.h
> > > +++ b/arch/powerpc/include/asm/inst.h
> > > @@ -8,23 +8,67 @@
> > >
> > > struct ppc_inst {
> > >
> > > u32 val;
> > >
> > > +#ifdef __powerpc64__
> > > + u32 suffix;
> > > +#endif /* __powerpc64__ */
> > >
> > > } __packed;
> > >
> > > -#define ppc_inst(x) ((struct ppc_inst){ .val = x })
> > > +static inline int ppc_inst_opcode(struct ppc_inst x)
> > > +{
> > > + return x.val >> 26;
> > > +}
> > >
> > > static inline u32 ppc_inst_val(struct ppc_inst x)
> > > {
> > >
> > > return x.val;
> > >
> > > }
> > >
> > > -static inline bool ppc_inst_len(struct ppc_inst x)
> > > +#ifdef __powerpc64__
> > > +#define ppc_inst(x) ((struct ppc_inst){ .val = (x), .suffix = 0xff })
> > > +
> > > +#define ppc_inst_prefix(x, y) ((struct ppc_inst){ .val = (x), .suffix =
> >
> > (y)
> >
> > > }) +
> > > +static inline u32 ppc_inst_suffix(struct ppc_inst x)
> > >
> > > {
> > >
> > > - return sizeof(struct ppc_inst);
> > > + return x.suffix;
> > >
> > > }
> > >
> > > -static inline int ppc_inst_opcode(struct ppc_inst x)
> > > +static inline bool ppc_inst_prefixed(struct ppc_inst x) {
> > > + return ((ppc_inst_val(x) >> 26) == 1) && ppc_inst_suffix(x) !=
> >
> > 0xff;
> >
> > > +}
> > > +
> > > +static inline struct ppc_inst ppc_inst_swab(struct ppc_inst x)
> > >
> > > {
> > >
> > > - return x.val >> 26;
> > > + return ppc_inst_prefix(swab32(ppc_inst_val(x)),
> > > + swab32(ppc_inst_suffix(x)));
> > > +}
> > > +
> > > +static inline struct ppc_inst ppc_inst_read(const struct ppc_inst *ptr)
> > > +{
> > > + u32 val, suffix = 0xff;
> > > + val = *(u32 *)ptr;
> > > + if ((val >> 26) == 1)
> > > + suffix = *((u32 *)ptr + 1);
> > > + return ppc_inst_prefix(val, suffix);
> > > +}
> > > +
> > > +static inline void ppc_inst_write(struct ppc_inst *ptr, struct ppc_inst
> >
> > x)
> >
> > > +{
> > > + if (ppc_inst_prefixed(x)) {
> > > + *(u32 *)ptr = x.val;
> > > + *((u32 *)ptr + 1) = x.suffix;
> > > + } else {
> > > + *(u32 *)ptr = x.val;
> > > + }
> > > +}
> > > +
> > > +#else
> > > +
> > > +#define ppc_inst(x) ((struct ppc_inst){ .val = x })
> > > +
> > > +static inline bool ppc_inst_prefixed(ppc_inst x)
> > > +{
> > > + return 0;
> > >
> > > }
> > >
> > > static inline struct ppc_inst ppc_inst_swab(struct ppc_inst x)
> > >
> > > @@ -32,14 +76,31 @@ static inline struct ppc_inst ppc_inst_swab(struct
> > > ppc_inst x) return ppc_inst(swab32(ppc_inst_val(x)));
> > >
> > > }
> > >
> > > +static inline u32 ppc_inst_val(struct ppc_inst x)
> > > +{
> > > + return x.val;
> > > +}
> > > +
> > >
> > > static inline struct ppc_inst ppc_inst_read(const struct ppc_inst *ptr)
> > > {
> > >
> > > return *ptr;
> > >
> > > }
> > >
> > > +static inline void ppc_inst_write(struct ppc_inst *ptr, struct ppc_inst
> >
> > x)
> >
> > > +{
> > > + *ptr = x;
> > > +}
> > > +
> > > +#endif /* __powerpc64__ */
> > > +
> > >
> > > static inline bool ppc_inst_equal(struct ppc_inst x, struct ppc_inst y)
> > > {
> > >
> > > return !memcmp(&x, &y, sizeof(struct ppc_inst));
> > >
> > > }
> >
> > Apologies for not picking this up earlier, I was hoping to get to the
> > bottom
> > of the issue I was seeing before you sent out v5. However the above
> > definition
> > of instruction equality does not seem correct because it does not consider
> > the
> > case when an instruction is not prefixed - a non-prefixed instruction
> > should be
> > considered equal if the first 32-bit opcode/value is the same. Something
> >
> > like:
> > if (ppc_inst_prefixed(x) != ppc_inst_prefixed(y))
> >
> > return false;
> >
> > else if (ppc_inst_prefixed(x))
> >
> > return !memcmp(&x, &y, sizeof(struct ppc_inst));
> >
> > else
> >
> > return x.val == y.val;
> >
> > This was causing failures in ftrace_modify_code() as it would falsely
> > detect
> > two non-prefixed instructions as being not equal due to differences in the
> > suffix.
>
> Hm I was intending that non prefixed instructions would always have the
> suffix set to the same value. If that's not happening, something must be
> wrong with where the instructions are created.
>
Ok, based on your comment I found the problem. Your last patch series defined
read_inst() in ftrace.c and ended that function with:
ppc_inst_write(p, inst);
return 0;
This is called from ftrace_modify_code(), where p is uninitialised. In the
last series ppc_inst_write() function would only write/initialise the suffix if
it was a prefixed instruction, hence leaving it uninitialised in this instance
which lead to the problems checking equality.
I suspect read_instr() should have finished with this instead:
*p = inst;
return 0;
However your new patch series replaces it with probe_kernel_read_inst() which
looks to do the right thing:
+ *inst = ppc_inst_prefix(val, suffix);
+
+ return 0;
As the suffix in *inst will always get written now, so my previous comment
appears invalid.
- Alistair
> > - Alistair
> >
> > > +static inline int ppc_inst_len(struct ppc_inst x)
> > > +{
> > > + return (ppc_inst_prefixed(x)) ? 8 : 4;
> > > +}
> > > +
> > >
> > > #endif /* _ASM_INST_H */
> > >
> > > diff --git a/arch/powerpc/include/asm/kprobes.h
> > > b/arch/powerpc/include/asm/kprobes.h index 66b3f2983b22..4fc0e15e23a5
> > > 100644
> > > --- a/arch/powerpc/include/asm/kprobes.h
> > > +++ b/arch/powerpc/include/asm/kprobes.h
> > > @@ -43,7 +43,7 @@ extern kprobe_opcode_t optprobe_template_ret[];
> > >
> > > extern kprobe_opcode_t optprobe_template_end[];
> > >
> > > /* Fixed instruction size for powerpc */
> > >
> > > -#define MAX_INSN_SIZE 1
> > > +#define MAX_INSN_SIZE 2
> > >
> > > #define MAX_OPTIMIZED_LENGTH sizeof(kprobe_opcode_t) /* 4 bytes */
> > > #define MAX_OPTINSN_SIZE (optprobe_template_end -
> >
> > optprobe_template_entry)
> >
> > > #define RELATIVEJUMP_SIZE sizeof(kprobe_opcode_t) /* 4 bytes */
> > >
> > > diff --git a/arch/powerpc/include/asm/uaccess.h
> > > b/arch/powerpc/include/asm/uaccess.h index c0a35e4586a5..5a3f486ddf02
> > > 100644
> > > --- a/arch/powerpc/include/asm/uaccess.h
> > > +++ b/arch/powerpc/include/asm/uaccess.h
> > > @@ -105,11 +105,34 @@ static inline int __access_ok(unsigned long addr,
> > > unsigned long size, #define __put_user_inatomic(x, ptr) \
> > >
> > > __put_user_nosleep((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
> > >
> > > -#define __get_user_instr(x, ptr) \
> > > - __get_user_nocheck((x).val, (u32 *)(ptr), sizeof(u32), true)
> > > +#define __get_user_instr(x, ptr) \
> > > +({ \
> > > + long __gui_ret = 0; \
> > > + unsigned int prefix, suffix; \
> > > + __gui_ret = __get_user(prefix, (unsigned int __user *)ptr);
> > >
> > \
> > >
> > > + if (!__gui_ret && (prefix >> 26) == 1) { \
> > > + __gui_ret = __get_user(suffix, (unsigned int __user *)ptr
> >
> > + 1); \
> >
> > > + (x) = ppc_inst_prefix(prefix, suffix); \
> > > + } else { \
> > > + (x) = ppc_inst(prefix); \
> > > + } \
> > > + __gui_ret; \
> > > +})
> > > +
> > > +#define __get_user_instr_inatomic(x, ptr) \
> > > +({ \
> > > + long __gui_ret = 0; \
> > > + unsigned int prefix, suffix; \
> > > + __gui_ret = __get_user_inatomic(prefix, (unsigned int __user
> >
> > *)ptr); \
> >
> > > + if (!__gui_ret && (prefix >> 26) == 1) { \
> > > + __gui_ret = __get_user_inatomic(suffix, (unsigned int
> >
> > __user *)ptr +
> >
> > > 1); \ + (x) = ppc_inst_prefix(prefix, suffix); \
> > > + } else { \
> > > + (x) = ppc_inst(prefix); \
> > > + } \
> > > + __gui_ret; \
> > > +})
> > >
> > > -#define __get_user_instr_inatomic(x, ptr) \
> > > - __get_user_nosleep((x).val, (u32 *)(ptr), sizeof(u32))
> > >
> > > extern long __put_user_bad(void);
> > >
> > > /*
> > >
> > > diff --git a/arch/powerpc/include/asm/uprobes.h
> > > b/arch/powerpc/include/asm/uprobes.h index 7e3b329ba2d3..5bf65f5d44a9
> > > 100644
> > > --- a/arch/powerpc/include/asm/uprobes.h
> > > +++ b/arch/powerpc/include/asm/uprobes.h
> > > @@ -15,7 +15,7 @@
> > >
> > > typedef ppc_opcode_t uprobe_opcode_t;
> > >
> > > -#define MAX_UINSN_BYTES 4
> > > +#define MAX_UINSN_BYTES 8
> > >
> > > #define UPROBE_XOL_SLOT_BYTES (MAX_UINSN_BYTES)
> > >
> > > /* The following alias is needed for reference from arch-agnostic code
> >
> > */
> >
> > > diff --git a/arch/powerpc/kernel/optprobes.c
> > > b/arch/powerpc/kernel/optprobes.c index 684640b8fa2e..689daf430161
> > > 100644
> > > --- a/arch/powerpc/kernel/optprobes.c
> > > +++ b/arch/powerpc/kernel/optprobes.c
> > > @@ -159,38 +159,38 @@ void patch_imm32_load_insns(unsigned int val,
> > > kprobe_opcode_t *addr)
> > >
> > > /*
> > >
> > > * Generate instructions to load provided immediate 64-bit value
> > >
> > > - * to register 'r3' and patch these instructions at 'addr'.
> > > + * to register 'reg' and patch these instructions at 'addr'.
> > >
> > > */
> > >
> > > -void patch_imm64_load_insns(unsigned long val, kprobe_opcode_t *addr)
> > > +void patch_imm64_load_insns(unsigned long val, int reg, kprobe_opcode_t
> > > *addr) {
> > > - /* lis r3,(op)@highest */
> > > - patch_instruction((struct ppc_inst *)addr, ppc_inst(PPC_INST_ADDIS
> > >
> > > ___PPC_RT(3) | + /* lis reg,(op)@highest */
> > > + patch_instruction((struct ppc_inst *)addr, ppc_inst(PPC_INST_ADDIS
> > >
> > > ___PPC_RT(reg) | ((val >> 48) & 0xffff)));
> > >
> > > addr++;
> > >
> > > - /* ori r3,r3,(op)@higher */
> > > - patch_instruction((struct ppc_inst *)addr, ppc_inst(PPC_INST_ORI |
> > > ___PPC_RA(3) | - ___PPC_RS(3) | ((val >> 32) &
> >
> > 0xffff)));
> >
> > > + /* ori reg,reg,(op)@higher */
> > > + patch_instruction((struct ppc_inst *)addr, ppc_inst(PPC_INST_ORI |
> > > ___PPC_RA(reg) | + ___PPC_RS(reg) | ((val >> 32) &
> >
> > 0xffff)));
> >
> > > addr++;
> > >
> > > - /* rldicr r3,r3,32,31 */
> > > - patch_instruction((struct ppc_inst *)addr,
> >
> > ppc_inst(PPC_INST_RLDICR |
> >
> > > ___PPC_RA(3) | - ___PPC_RS(3) | __PPC_SH64(32) |
> >
> > __PPC_ME64(31)));
> >
> > > + /* rldicr reg,reg,32,31 */
> > > + patch_instruction((struct ppc_inst *)addr,
> >
> > ppc_inst(PPC_INST_RLDICR |
> >
> > > ___PPC_RA(reg) | + ___PPC_RS(reg) | __PPC_SH64(32)
> >
> > __PPC_ME64(31)));
> >
> > > addr++;
> > >
> > > - /* oris r3,r3,(op)@h */
> > > - patch_instruction((struct ppc_inst *)addr, ppc_inst(PPC_INST_ORIS
> > > |
> > > ___PPC_RA(3) | - ___PPC_RS(3) | ((val >> 16) &
> >
> > 0xffff)));
> >
> > > + /* oris reg,reg,(op)@h */
> > > + patch_instruction((struct ppc_inst *)addr, ppc_inst(PPC_INST_ORIS
> > > |
> > > ___PPC_RA(reg) | + ___PPC_RS(reg) | ((val >> 16) &
> >
> > 0xffff)));
> >
> > > addr++;
> > >
> > > - /* ori r3,r3,(op)@l */
> > > - patch_instruction((struct ppc_inst *)addr, ppc_inst(PPC_INST_ORI |
> > > ___PPC_RA(3) | - ___PPC_RS(3) | (val & 0xffff)));
> > > + /* ori reg,reg,(op)@l */
> > > + patch_instruction((struct ppc_inst *)addr, ppc_inst(PPC_INST_ORI |
> > > ___PPC_RA(reg) | + ___PPC_RS(reg) | (val &
> >
> > 0xffff)));
> >
> > > }
> > >
> > > int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, struct
> > >
> > > kprobe *p) {
> > > - struct ppc_inst branch_op_callback, branch_emulate_step;
> > > + struct ppc_inst branch_op_callback, branch_emulate_step, temp;
> > >
> > > kprobe_opcode_t *op_callback_addr, *emulate_step_addr, *buff;
> > > long b_offset;
> > > unsigned long nip, size;
> > >
> > > @@ -240,7 +240,7 @@ int arch_prepare_optimized_kprobe(struct
> > > optimized_kprobe *op, struct kprobe *p) * Fixup the template with
> > >
> > > instructions to:
> > > * 1. load the address of the actual probepoint
> > > */
> > >
> > > - patch_imm64_load_insns((unsigned long)op, buff + TMPL_OP_IDX);
> > > + patch_imm64_load_insns((unsigned long)op, 3, buff + TMPL_OP_IDX);
> > >
> > > /*
> > >
> > > * 2. branch to optimized_callback() and emulate_step()
> > >
> > > @@ -271,7 +271,11 @@ int arch_prepare_optimized_kprobe(struct
> > > optimized_kprobe *op, struct kprobe *p) /*
> > >
> > > * 3. load instruction to be emulated into relevant register, and
> > > */
> > >
> > > - patch_imm32_load_insns(*p->ainsn.insn, buff + TMPL_INSN_IDX);
> > > + temp = ppc_inst_read((struct ppc_inst *)p->ainsn.insn);
> > > + patch_imm64_load_insns(ppc_inst_val(temp) |
> > > + ((u64)ppc_inst_suffix(temp) << 32),
> > > + 4,
> > > + buff + TMPL_INSN_IDX);
> > >
> > > /*
> > >
> > > * 4. branch back from trampoline
> > >
> > > diff --git a/arch/powerpc/kernel/optprobes_head.S
> > > b/arch/powerpc/kernel/optprobes_head.S index cf383520843f..ff8ba4d3824d
> > > 100644
> > > --- a/arch/powerpc/kernel/optprobes_head.S
> > > +++ b/arch/powerpc/kernel/optprobes_head.S
> > >
> > > @@ -94,6 +94,9 @@ optprobe_template_insn:
> > > /* 2, Pass instruction to be emulated in r4 */
> > > nop
> > > nop
> > >
> > > + nop
> > > + nop
> > > + nop
> > >
> > > .global optprobe_template_call_emulate
> > >
> > > optprobe_template_call_emulate:
> > > diff --git a/arch/powerpc/kernel/trace/ftrace.c
> > > b/arch/powerpc/kernel/trace/ftrace.c index e78742613b36..16041a5c86d5
> > > 100644
> > > --- a/arch/powerpc/kernel/trace/ftrace.c
> > > +++ b/arch/powerpc/kernel/trace/ftrace.c
> > > @@ -41,11 +41,35 @@
> > >
> > > #define NUM_FTRACE_TRAMPS 8
> > > static unsigned long ftrace_tramps[NUM_FTRACE_TRAMPS];
> > >
> > > +#ifdef __powerpc64__
> > >
> > > static long
> > > probe_kernel_read_inst(struct ppc_inst *inst, const void *src)
> > > {
> > >
> > > - return probe_kernel_read((void *)inst, src, MCOUNT_INSN_SIZE);
> > > + u32 val, suffix = 0;
> > > + long err;
> > > +
> > > + err = probe_kernel_read((void *)&val,
> > > + src, sizeof(val));
> > > + if (err)
> > > + return err;
> > > +
> > > + if ((val >> 26) == 1)
> > > + err = probe_kernel_read((void *)&suffix,
> > > + src + 4, MCOUNT_INSN_SIZE);
> > > + if (err)
> > > + return err;
> > > +
> > > + *inst = ppc_inst_prefix(val, suffix);
> > > +
> > > + return 0;
> > >
> > > }
> > >
> > > +#else
> > > +static long
> > > +probe_kernel_read_inst(struct ppc_inst *inst, const void *src)
> > > +{
> > > + return probe_kernel_read((void *)inst, src, MCOUNT_INSN_SIZE)
> > > +}
> > > +#endif
> > >
> > > static struct ppc_inst
> > > ftrace_call_replace(unsigned long ip, unsigned long addr, int link)
> > >
> > > diff --git a/arch/powerpc/lib/code-patching.c
> > > b/arch/powerpc/lib/code-patching.c index c329ad657302..b4007e03d8fa
> >
> > 100644
> >
> > > --- a/arch/powerpc/lib/code-patching.c
> > > +++ b/arch/powerpc/lib/code-patching.c
> > > @@ -24,12 +24,19 @@ static int __patch_instruction(struct ppc_inst
> > > *exec_addr, struct ppc_inst instr {
> > >
> > > int err = 0;
> > >
> > > - __put_user_asm(ppc_inst_val(instr), patch_addr, err, "stw");
> > > - if (err)
> > > - return err;
> > > -
> > > - asm ("dcbst 0, %0; sync; icbi 0,%1; sync; isync" :: "r"
> >
> > (patch_addr),
> >
> > > - "r"
> >
> > (exec_addr));
> >
> > > + if (!ppc_inst_prefixed(instr)) {
> > > + __put_user_asm(ppc_inst_val(instr), patch_addr, err,
> >
> > "stw");
> >
> > > + if (err)
> > > + return err;
> > > + asm ("dcbst 0, %0; sync; icbi 0,%1; sync; isync" :: "r"
> >
> > (patch_addr),
> >
> > > + "r"
> >
> > (exec_addr));
> >
> > > + } else {
> > > + __put_user_asm((u64)ppc_inst_suffix(instr) << 32 |
> >
> > ppc_inst_val(instr),
> >
> > > patch_addr, err, "std"); + if (err)
> > > + return err;
> > > + asm ("dcbst 0, %0; sync; icbi 0,%1; sync; isync" :: "r"
> >
> > (patch_addr),
> >
> > > + "r"
> >
> > (exec_addr));
> >
> > > + }
> > >
> > > return 0;
> > >
> > > }
> > >
> > > diff --git a/arch/powerpc/lib/feature-fixups.c
> > > b/arch/powerpc/lib/feature-fixups.c index f00dd13b1c3c..5519cec83cc8
> >
> > 100644
> >
> > > --- a/arch/powerpc/lib/feature-fixups.c
> > > +++ b/arch/powerpc/lib/feature-fixups.c
> > > @@ -84,12 +84,13 @@ static int patch_feature_section(unsigned long
> > > value,
> > > struct fixup_entry *fcur) src = alt_start;
> > >
> > > dest = start;
> > >
> > > - for (; src < alt_end; src++, dest++) {
> > > + for (; src < alt_end; src = (void *)src +
> > > ppc_inst_len(ppc_inst_read(src)), + (dest = (void *)dest +
> > > ppc_inst_len(ppc_inst_read(dest)))) { if (patch_alt_instruction(src,
> >
> > dest,
> >
> > > alt_start, alt_end))
> > >
> > > return 1;
> > >
> > > }
> > >
> > > - for (; dest < end; dest++)
> > > + for (; dest < end; dest = (void *)dest +
> > > ppc_inst_len(ppc_inst(PPC_INST_NOP))) raw_patch_instruction(dest,
> > > ppc_inst(PPC_INST_NOP));
> > >
> > > return 0;
> > >
> > > diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
> > > index 52ddd3122dc8..8b285bf11218 100644
> > > --- a/arch/powerpc/lib/sstep.c
> > > +++ b/arch/powerpc/lib/sstep.c
> > > @@ -1169,10 +1169,12 @@ int analyse_instr(struct instruction_op *op,
> >
> > const
> >
> > > struct pt_regs *regs, unsigned long int imm;
> > >
> > > unsigned long int val, val2;
> > > unsigned int mb, me, sh;
> > >
> > > - unsigned int word;
> > > + unsigned int word, suffix;
> > >
> > > long ival;
> > >
> > > word = ppc_inst_val(instr);
> > >
> > > + suffix = ppc_inst_suffix(instr);
> > > +
> > >
> > > op->type = COMPUTE;
> > >
> > > opcode = word >> 26;
> > >
> > > diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
> > > index 6f3bcdcfc9c7..b704aebb099a 100644
> > > --- a/arch/powerpc/xmon/xmon.c
> > > +++ b/arch/powerpc/xmon/xmon.c
> > > @@ -761,8 +761,8 @@ static int xmon_bpt(struct pt_regs *regs)
> > >
> > > /* Are we at the trap at bp->instr[1] for some bp? */
> > > bp = in_breakpoint_table(regs->nip, &offset);
> > >
> > > - if (bp != NULL && offset == 4) {
> > > - regs->nip = bp->address + 4;
> > > + if (bp != NULL && (offset == 4 || offset == 8)) {
> > > + regs->nip = bp->address + offset;
> > >
> > > atomic_dec(&bp->ref_count);
> > > return 1;
> > >
> > > }
> > >
> > > @@ -863,7 +863,7 @@ static struct bpt *in_breakpoint_table(unsigned long
> > > nip, unsigned long *offp) if (off >= sizeof(bpt_table))
> > >
> > > return NULL;
> > >
> > > *offp = off % BPT_SIZE;
> > >
> > > - if (*offp != 0 && *offp != 4)
> > > + if (*offp != 0 && *offp != 4 && *offp != 8)
> > >
> > > return NULL;
> > >
> > > return bpts + (off / BPT_SIZE);
> > >
> > > }
> > >
> > > diff --git a/arch/powerpc/xmon/xmon_bpts.S
> >
> > b/arch/powerpc/xmon/xmon_bpts.S
> >
> > > index ebb2dbc70ca8..09058eb6abbd 100644
> > > --- a/arch/powerpc/xmon/xmon_bpts.S
> > > +++ b/arch/powerpc/xmon/xmon_bpts.S
> > > @@ -3,6 +3,8 @@
> > >
> > > #include <asm/asm-compat.h>
> > > #include "xmon_bpts.h"
> > >
> > > +/* Prefixed instructions can not cross 64 byte boundaries */
> > > +.align 6
> > >
> > > .global bpt_table
> > >
> > > bpt_table:
> > > - .space NBPTS * 8
> > > + .space NBPTS * 16
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