On Mon, 2020-04-06 at 18:09 +1000, Jordan Niethe wrote: > create_branch(), create_cond_branch() and translate_branch() return the > instruction that they create, or return 0 to signal an error. Seperate
s/seperate/separate > these concerns in preparation for an instruction type that is not just > an unsigned int. Fill the created instruction to a pointer passed as > the first parameter to the function and use a non-zero return value to > signify an error. > > Signed-off-by: Jordan Niethe <jniet...@gmail.com> > --- > v5: New to series > --- > arch/powerpc/include/asm/code-patching.h | 12 +- > arch/powerpc/kernel/optprobes.c | 24 ++-- > arch/powerpc/kernel/setup_32.c | 2 +- > arch/powerpc/kernel/trace/ftrace.c | 24 ++-- > arch/powerpc/lib/code-patching.c | 133 +++++++++++++---------- > arch/powerpc/lib/feature-fixups.c | 5 +- > 6 files changed, 117 insertions(+), 83 deletions(-) > > diff --git a/arch/powerpc/include/asm/code-patching.h > b/arch/powerpc/include/asm/code-patching.h > index 898b54262881..351dda7215b6 100644 > --- a/arch/powerpc/include/asm/code-patching.h > +++ b/arch/powerpc/include/asm/code-patching.h > @@ -22,10 +22,10 @@ > #define BRANCH_ABSOLUTE 0x2 > > bool is_offset_in_branch_range(long offset); > -unsigned int create_branch(const unsigned int *addr, > - unsigned long target, int flags); > -unsigned int create_cond_branch(const unsigned int *addr, > - unsigned long target, int flags); > +int create_branch(unsigned int *instr, const unsigned int *addr, > + unsigned long target, int flags); > +int create_cond_branch(unsigned int *instr, const unsigned int *addr, > + unsigned long target, int flags); > int patch_branch(unsigned int *addr, unsigned long target, int flags); > int patch_instruction(unsigned int *addr, unsigned int instr); > int raw_patch_instruction(unsigned int *addr, unsigned int instr); > @@ -60,8 +60,8 @@ int instr_is_relative_branch(unsigned int instr); > int instr_is_relative_link_branch(unsigned int instr); > int instr_is_branch_to_addr(const unsigned int *instr, unsigned long addr); > unsigned long branch_target(const unsigned int *instr); > -unsigned int translate_branch(const unsigned int *dest, > - const unsigned int *src); > +int translate_branch(unsigned int *instr, const unsigned int *dest, > + const unsigned int *src); > extern bool is_conditional_branch(unsigned int instr); > #ifdef CONFIG_PPC_BOOK3E_64 > void __patch_exception(int exc, unsigned long addr); > diff --git a/arch/powerpc/kernel/optprobes.c > b/arch/powerpc/kernel/optprobes.c > index 024f7aad1952..445b3dad82dc 100644 > --- a/arch/powerpc/kernel/optprobes.c > +++ b/arch/powerpc/kernel/optprobes.c > @@ -251,15 +251,17 @@ int arch_prepare_optimized_kprobe(struct > optimized_kprobe *op, struct kprobe *p) > goto error; > } > > - branch_op_callback = create_branch((unsigned int *)buff + > TMPL_CALL_HDLR_IDX, > - (unsigned long)op_callback_addr, > - BRANCH_SET_LINK); > + rc = create_branch(&branch_op_callback, > + (unsigned int *)buff + TMPL_CALL_HDLR_IDX, > + (unsigned long)op_callback_addr, > + BRANCH_SET_LINK); > > - branch_emulate_step = create_branch((unsigned int *)buff + > TMPL_EMULATE_IDX, > - (unsigned long)emulate_step_addr, > - BRANCH_SET_LINK); > + rc |= create_branch(&branch_emulate_step, > + (unsigned int *)buff + TMPL_EMULATE_IDX, > + (unsigned long)emulate_step_addr, > + BRANCH_SET_LINK); > > - if (!branch_op_callback || !branch_emulate_step) > + if (rc) > goto error; > > patch_instruction(buff + TMPL_CALL_HDLR_IDX, branch_op_callback); > @@ -305,6 +307,7 @@ int arch_check_optimized_kprobe(struct optimized_kprobe > *op) > > void arch_optimize_kprobes(struct list_head *oplist) > { > + unsigned int instr; > struct optimized_kprobe *op; > struct optimized_kprobe *tmp; > > @@ -315,9 +318,10 @@ void arch_optimize_kprobes(struct list_head *oplist) > */ > memcpy(op->optinsn.copied_insn, op->kp.addr, > RELATIVEJUMP_SIZE); > - patch_instruction(op->kp.addr, > - create_branch((unsigned int *)op->kp.addr, > - (unsigned long)op->optinsn.insn, 0)); > + create_branch(&instr, > + (unsigned int *)op->kp.addr, > + (unsigned long)op->optinsn.insn, 0); > + patch_instruction(op->kp.addr, instr); > list_del_init(&op->list); > } > } > diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c > index 5b49b26eb154..c1bdd462c5c0 100644 > --- a/arch/powerpc/kernel/setup_32.c > +++ b/arch/powerpc/kernel/setup_32.c > @@ -88,7 +88,7 @@ notrace void __init machine_init(u64 dt_ptr) > > patch_instruction_site(&patch__memcpy_nocache, PPC_INST_NOP); > > - insn = create_cond_branch(addr, branch_target(addr), 0x820000); > + create_cond_branch(&insn, addr, branch_target(addr), 0x820000); > patch_instruction(addr, insn); /* replace b by bne cr0 */ > > /* Do some early initialization based on the flat device tree */ > diff --git a/arch/powerpc/kernel/trace/ftrace.c > b/arch/powerpc/kernel/trace/ftrace.c > index 7ea0ca044b65..4dcb379133f8 100644 > --- a/arch/powerpc/kernel/trace/ftrace.c > +++ b/arch/powerpc/kernel/trace/ftrace.c > @@ -48,7 +48,7 @@ ftrace_call_replace(unsigned long ip, unsigned long addr, > int link) > addr = ppc_function_entry((void *)addr); > > /* if (link) set op to 'bl' else 'b' */ > - op = create_branch((unsigned int *)ip, addr, link ? 1 : 0); > + create_branch(&op, (unsigned int *)ip, addr, link ? 1 : 0); > > return op; > } > @@ -89,10 +89,11 @@ ftrace_modify_code(unsigned long ip, unsigned int old, > unsigned int new) > */ > static int test_24bit_addr(unsigned long ip, unsigned long addr) > { > + unsigned int op; > addr = ppc_function_entry((void *)addr); > > /* use the create_branch to verify that this offset can be branched */ > - return create_branch((unsigned int *)ip, addr, 0); > + return create_branch(&op, (unsigned int *)ip, addr, 0) == 0; > } > > static int is_bl_op(unsigned int op) > @@ -287,6 +288,7 @@ __ftrace_make_nop(struct module *mod, > static unsigned long find_ftrace_tramp(unsigned long ip) > { > int i; > + unsigned int instr; > > /* > * We have the compiler generated long_branch tramps at the end > @@ -295,7 +297,8 @@ static unsigned long find_ftrace_tramp(unsigned long ip) > for (i = NUM_FTRACE_TRAMPS - 1; i >= 0; i--) > if (!ftrace_tramps[i]) > continue; > - else if (create_branch((void *)ip, ftrace_tramps[i], 0)) > + else if (create_branch(&instr, (void *)ip, > + ftrace_tramps[i], 0) == 0) > return ftrace_tramps[i]; > > return 0; > @@ -324,6 +327,7 @@ static int setup_mcount_compiler_tramp(unsigned long > tramp) > { > int i, op; > unsigned long ptr; > + unsigned int instr; > static unsigned long ftrace_plt_tramps[NUM_FTRACE_TRAMPS]; > > /* Is this a known long jump tramp? */ > @@ -366,7 +370,7 @@ static int setup_mcount_compiler_tramp(unsigned long > tramp) > #else > ptr = ppc_global_function_entry((void *)ftrace_caller); > #endif > - if (!create_branch((void *)tramp, ptr, 0)) { > + if (create_branch(&instr, (void *)tramp, ptr, 0)) { > pr_debug("%ps is not reachable from existing mcount tramp\n", > (void *)ptr); > return -1; > @@ -511,6 +515,7 @@ static int > __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) > { > unsigned int op[2]; > + unsigned int instr; > void *ip = (void *)rec->ip; > unsigned long entry, ptr, tramp; > struct module *mod = rec->arch.mod; > @@ -557,7 +562,7 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long > addr) > } > > /* Ensure branch is within 24 bits */ > - if (!create_branch(ip, tramp, BRANCH_SET_LINK)) { > + if (create_branch(&instr, ip, tramp, BRANCH_SET_LINK)) { > pr_err("Branch out of range\n"); > return -EINVAL; > } > @@ -574,6 +579,7 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long > addr) > static int > __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) > { > + int err; > unsigned int op; > unsigned long ip = rec->ip; > > @@ -594,9 +600,9 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long > addr) > } > > /* create the branch to the trampoline */ > - op = create_branch((unsigned int *)ip, > - rec->arch.mod->arch.tramp, BRANCH_SET_LINK); > - if (!op) { > + err = create_branch(&op, (unsigned int *)ip, > + rec->arch.mod->arch.tramp, BRANCH_SET_LINK); > + if (!err) { should this be `if (err)` as per your new changes ? > pr_err("REL24 out of range!\n"); > return -EINVAL; > } > @@ -776,7 +782,7 @@ __ftrace_modify_call(struct dyn_ftrace *rec, unsigned > long old_addr, > } > > /* Ensure branch is within 24 bits */ > - if (!create_branch((unsigned int *)ip, tramp, BRANCH_SET_LINK)) { > + if (create_branch(&op, (unsigned int *)ip, tramp, BRANCH_SET_LINK)) { > pr_err("Branch out of range\n"); > return -EINVAL; > } > diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code- > patching.c > index 3345f039a876..4af564aeedf1 100644 > --- a/arch/powerpc/lib/code-patching.c > +++ b/arch/powerpc/lib/code-patching.c > @@ -196,7 +196,10 @@ NOKPROBE_SYMBOL(patch_instruction); > > int patch_branch(unsigned int *addr, unsigned long target, int flags) > { > - return patch_instruction(addr, create_branch(addr, target, flags)); > + unsigned int instr; > + > + create_branch(&instr, addr, target, flags); > + return patch_instruction(addr, instr); > } > > bool is_offset_in_branch_range(long offset) > @@ -243,30 +246,30 @@ bool is_conditional_branch(unsigned int instr) > } > NOKPROBE_SYMBOL(is_conditional_branch); > > -unsigned int create_branch(const unsigned int *addr, > - unsigned long target, int flags) > +int create_branch(unsigned int *instr, > + const unsigned int *addr, > + unsigned long target, int flags) > { > - unsigned int instruction; > long offset; > > + *instr = 0; > offset = target; > if (! (flags & BRANCH_ABSOLUTE)) > offset = offset - (unsigned long)addr; > > /* Check we can represent the target in the instruction format */ > if (!is_offset_in_branch_range(offset)) > - return 0; > + return 1; > > /* Mask out the flags and target, so they don't step on each other. */ > - instruction = 0x48000000 | (flags & 0x3) | (offset & 0x03FFFFFC); > + *instr = 0x48000000 | (flags & 0x3) | (offset & 0x03FFFFFC); > > - return instruction; > + return 0; > } > > -unsigned int create_cond_branch(const unsigned int *addr, > - unsigned long target, int flags) > +int create_cond_branch(unsigned int *instr, const unsigned int *addr, > + unsigned long target, int flags) > { > - unsigned int instruction; > long offset; > > offset = target; > @@ -275,12 +278,12 @@ unsigned int create_cond_branch(const unsigned int > *addr, > > /* Check we can represent the target in the instruction format */ > if (offset < -0x8000 || offset > 0x7FFF || offset & 0x3) > - return 0; > + return 1; > > /* Mask out the flags and target, so they don't step on each other. */ > - instruction = 0x40000000 | (flags & 0x3FF0003) | (offset & 0xFFFC); > + *instr = 0x40000000 | (flags & 0x3FF0003) | (offset & 0xFFFC); > > - return instruction; > + return 0; > } > > static unsigned int branch_opcode(unsigned int instr) > @@ -361,18 +364,18 @@ int instr_is_branch_to_addr(const unsigned int *instr, > unsigned long addr) > return 0; > } > > -unsigned int translate_branch(const unsigned int *dest, const unsigned int > *src) > +int translate_branch(unsigned int *instr, const unsigned int *dest, const > unsigned int *src) > { > unsigned long target; > > target = branch_target(src); > > if (instr_is_branch_iform(*src)) > - return create_branch(dest, target, *src); > + return create_branch(instr, dest, target, *src); > else if (instr_is_branch_bform(*src)) > - return create_cond_branch(dest, target, *src); > + return create_cond_branch(instr, dest, target, *src); > > - return 0; > + return 1; > } > > #ifdef CONFIG_PPC_BOOK3E_64 > @@ -403,6 +406,7 @@ static void __init test_trampoline(void) > > static void __init test_branch_iform(void) > { > + int err; > unsigned int instr; > unsigned long addr; > > @@ -443,35 +447,35 @@ static void __init test_branch_iform(void) > check(instr_is_branch_to_addr(&instr, addr - 0x2000000)); > > /* Branch to self, with link */ > - instr = create_branch(&instr, addr, BRANCH_SET_LINK); > + err = create_branch(&instr, &instr, addr, BRANCH_SET_LINK); > check(instr_is_branch_to_addr(&instr, addr)); > > /* Branch to self - 0x100, with link */ > - instr = create_branch(&instr, addr - 0x100, BRANCH_SET_LINK); > + err = create_branch(&instr, &instr, addr - 0x100, BRANCH_SET_LINK); > check(instr_is_branch_to_addr(&instr, addr - 0x100)); > > /* Branch to self + 0x100, no link */ > - instr = create_branch(&instr, addr + 0x100, 0); > + err = create_branch(&instr, &instr, addr + 0x100, 0); > check(instr_is_branch_to_addr(&instr, addr + 0x100)); > > /* Maximum relative negative offset, - 32 MB */ > - instr = create_branch(&instr, addr - 0x2000000, BRANCH_SET_LINK); > + err = create_branch(&instr, &instr, addr - 0x2000000, BRANCH_SET_LINK); > check(instr_is_branch_to_addr(&instr, addr - 0x2000000)); > > /* Out of range relative negative offset, - 32 MB + 4*/ > - instr = create_branch(&instr, addr - 0x2000004, BRANCH_SET_LINK); > - check(instr == 0); > + err = create_branch(&instr, &instr, addr - 0x2000004, BRANCH_SET_LINK); > + check(err); > > /* Out of range relative positive offset, + 32 MB */ > - instr = create_branch(&instr, addr + 0x2000000, BRANCH_SET_LINK); > - check(instr == 0); > + err = create_branch(&instr, &instr, addr + 0x2000000, BRANCH_SET_LINK); > + check(err); > > /* Unaligned target */ > - instr = create_branch(&instr, addr + 3, BRANCH_SET_LINK); > - check(instr == 0); > + err = create_branch(&instr, &instr, addr + 3, BRANCH_SET_LINK); > + check(err); > > /* Check flags are masked correctly */ > - instr = create_branch(&instr, addr, 0xFFFFFFFC); > + err = create_branch(&instr, &instr, addr, 0xFFFFFFFC); > check(instr_is_branch_to_addr(&instr, addr)); > check(instr == 0x48000000); > } > @@ -480,16 +484,19 @@ static void __init test_create_function_call(void) > { > unsigned int *iptr; > unsigned long dest; > + unsigned int instr; > > /* Check we can create a function call */ > iptr = (unsigned int *)ppc_function_entry(test_trampoline); > dest = ppc_function_entry(test_create_function_call); > - patch_instruction(iptr, create_branch(iptr, dest, BRANCH_SET_LINK)); > + create_branch(&instr, iptr, dest, BRANCH_SET_LINK); > + patch_instruction(iptr, instr); Are we sure that `create_branch()` would always succeed here to do patch_instruction() ? > check(instr_is_branch_to_addr(iptr, dest)); > } > > static void __init test_branch_bform(void) > { > + int err; > unsigned long addr; > unsigned int *iptr, instr, flags; > > @@ -525,35 +532,35 @@ static void __init test_branch_bform(void) > flags = 0x3ff000 | BRANCH_SET_LINK; > > /* Branch to self */ > - instr = create_cond_branch(iptr, addr, flags); > + err = create_cond_branch(&instr, iptr, addr, flags); > check(instr_is_branch_to_addr(&instr, addr)); > > /* Branch to self - 0x100 */ > - instr = create_cond_branch(iptr, addr - 0x100, flags); > + err = create_cond_branch(&instr, iptr, addr - 0x100, flags); > check(instr_is_branch_to_addr(&instr, addr - 0x100)); > > /* Branch to self + 0x100 */ > - instr = create_cond_branch(iptr, addr + 0x100, flags); > + err = create_cond_branch(&instr, iptr, addr + 0x100, flags); > check(instr_is_branch_to_addr(&instr, addr + 0x100)); > > /* Maximum relative negative offset, - 32 KB */ > - instr = create_cond_branch(iptr, addr - 0x8000, flags); > + err = create_cond_branch(&instr, iptr, addr - 0x8000, flags); > check(instr_is_branch_to_addr(&instr, addr - 0x8000)); > > /* Out of range relative negative offset, - 32 KB + 4*/ > - instr = create_cond_branch(iptr, addr - 0x8004, flags); > - check(instr == 0); > + err = create_cond_branch(&instr, iptr, addr - 0x8004, flags); > + check(err); > > /* Out of range relative positive offset, + 32 KB */ > - instr = create_cond_branch(iptr, addr + 0x8000, flags); > - check(instr == 0); > + err = create_cond_branch(&instr, iptr, addr + 0x8000, flags); > + check(err); > > /* Unaligned target */ > - instr = create_cond_branch(iptr, addr + 3, flags); > - check(instr == 0); > + err = create_cond_branch(&instr, iptr, addr + 3, flags); > + check(err); > > /* Check flags are masked correctly */ > - instr = create_cond_branch(iptr, addr, 0xFFFFFFFC); > + err = create_cond_branch(&instr, iptr, addr, 0xFFFFFFFC); > check(instr_is_branch_to_addr(&instr, addr)); > check(instr == 0x43FF0000); > } > @@ -562,6 +569,7 @@ static void __init test_translate_branch(void) > { > unsigned long addr; > unsigned int *p, *q; > + unsigned int instr; > void *buf; > > buf = vmalloc(PAGE_ALIGN(0x2000000 + 1)); > @@ -575,7 +583,8 @@ static void __init test_translate_branch(void) > patch_branch(p, addr, 0); > check(instr_is_branch_to_addr(p, addr)); > q = p + 1; > - patch_instruction(q, translate_branch(q, p)); > + translate_branch(&instr, q, p); > + patch_instruction(q, instr); same here and elsewhere in similar such places where we do patch_instruction() -- Bala > check(instr_is_branch_to_addr(q, addr)); > > /* Maximum negative case, move b . to addr + 32 MB */ > @@ -583,7 +592,8 @@ static void __init test_translate_branch(void) > addr = (unsigned long)p; > patch_branch(p, addr, 0); > q = buf + 0x2000000; > - patch_instruction(q, translate_branch(q, p)); > + translate_branch(&instr, q, p); > + patch_instruction(q, instr); > check(instr_is_branch_to_addr(p, addr)); > check(instr_is_branch_to_addr(q, addr)); > check(*q == 0x4a000000); > @@ -593,7 +603,8 @@ static void __init test_translate_branch(void) > addr = (unsigned long)p; > patch_branch(p, addr, 0); > q = buf + 4; > - patch_instruction(q, translate_branch(q, p)); > + translate_branch(&instr, q, p); > + patch_instruction(q, instr); > check(instr_is_branch_to_addr(p, addr)); > check(instr_is_branch_to_addr(q, addr)); > check(*q == 0x49fffffc); > @@ -603,7 +614,8 @@ static void __init test_translate_branch(void) > addr = 0x1000000 + (unsigned long)buf; > patch_branch(p, addr, BRANCH_SET_LINK); > q = buf + 0x1400000; > - patch_instruction(q, translate_branch(q, p)); > + translate_branch(&instr, q, p); > + patch_instruction(q, instr); > check(instr_is_branch_to_addr(p, addr)); > check(instr_is_branch_to_addr(q, addr)); > > @@ -612,7 +624,8 @@ static void __init test_translate_branch(void) > addr = 0x2000000 + (unsigned long)buf; > patch_branch(p, addr, 0); > q = buf + 4; > - patch_instruction(q, translate_branch(q, p)); > + translate_branch(&instr, q, p); > + patch_instruction(q, instr); > check(instr_is_branch_to_addr(p, addr)); > check(instr_is_branch_to_addr(q, addr)); > > @@ -622,18 +635,22 @@ static void __init test_translate_branch(void) > /* Simple case, branch to self moved a little */ > p = buf; > addr = (unsigned long)p; > - patch_instruction(p, create_cond_branch(p, addr, 0)); > + create_cond_branch(&instr, p, addr, 0); > + patch_instruction(p, instr); > check(instr_is_branch_to_addr(p, addr)); > q = p + 1; > - patch_instruction(q, translate_branch(q, p)); > + translate_branch(&instr, q, p); > + patch_instruction(q, instr); > check(instr_is_branch_to_addr(q, addr)); > > /* Maximum negative case, move b . to addr + 32 KB */ > p = buf; > addr = (unsigned long)p; > - patch_instruction(p, create_cond_branch(p, addr, 0xFFFFFFFC)); > + create_cond_branch(&instr, p, addr, 0xFFFFFFFC); > + patch_instruction(p, instr); > q = buf + 0x8000; > - patch_instruction(q, translate_branch(q, p)); > + translate_branch(&instr, q, p); > + patch_instruction(q, instr); > check(instr_is_branch_to_addr(p, addr)); > check(instr_is_branch_to_addr(q, addr)); > check(*q == 0x43ff8000); > @@ -641,9 +658,11 @@ static void __init test_translate_branch(void) > /* Maximum positive case, move x to x - 32 KB + 4 */ > p = buf + 0x8000; > addr = (unsigned long)p; > - patch_instruction(p, create_cond_branch(p, addr, 0xFFFFFFFC)); > + create_cond_branch(&instr, p, addr, 0xFFFFFFFC); > + patch_instruction(p, instr); > q = buf + 4; > - patch_instruction(q, translate_branch(q, p)); > + translate_branch(&instr, q, p); > + patch_instruction(q, instr); > check(instr_is_branch_to_addr(p, addr)); > check(instr_is_branch_to_addr(q, addr)); > check(*q == 0x43ff7ffc); > @@ -651,18 +670,22 @@ static void __init test_translate_branch(void) > /* Jump to x + 12 KB moved to x + 20 KB */ > p = buf; > addr = 0x3000 + (unsigned long)buf; > - patch_instruction(p, create_cond_branch(p, addr, BRANCH_SET_LINK)); > + create_cond_branch(&instr, p, addr, BRANCH_SET_LINK); > + patch_instruction(p, instr); > q = buf + 0x5000; > - patch_instruction(q, translate_branch(q, p)); > + translate_branch(&instr, q, p); > + patch_instruction(q, instr); > check(instr_is_branch_to_addr(p, addr)); > check(instr_is_branch_to_addr(q, addr)); > > /* Jump to x + 8 KB moved to x - 8 KB + 4 */ > p = buf + 0x2000; > addr = 0x4000 + (unsigned long)buf; > - patch_instruction(p, create_cond_branch(p, addr, 0)); > + create_cond_branch(&instr, p, addr, 0); > + patch_instruction(p, instr); > q = buf + 4; > - patch_instruction(q, translate_branch(q, p)); > + translate_branch(&instr, q, p); > + patch_instruction(q, instr); > check(instr_is_branch_to_addr(p, addr)); > check(instr_is_branch_to_addr(q, addr)); > > diff --git a/arch/powerpc/lib/feature-fixups.c b/arch/powerpc/lib/feature- > fixups.c > index 4ba634b89ce5..b129d7b4e7dd 100644 > --- a/arch/powerpc/lib/feature-fixups.c > +++ b/arch/powerpc/lib/feature-fixups.c > @@ -44,6 +44,7 @@ static unsigned int *calc_addr(struct fixup_entry *fcur, > long offset) > static int patch_alt_instruction(unsigned int *src, unsigned int *dest, > unsigned int *alt_start, unsigned int > *alt_end) > { > + int err; > unsigned int instr; > > instr = *src; > @@ -53,8 +54,8 @@ static int patch_alt_instruction(unsigned int *src, > unsigned int *dest, > > /* Branch within the section doesn't need translating */ > if (target < alt_start || target > alt_end) { > - instr = translate_branch(dest, src); > - if (!instr) > + err = translate_branch(&instr, dest, src); > + if (err) > return 1; > } > }