From 95b980a00d1220ca67550a933166704db8bc5c14 Mon Sep 17 00:00:00 2001 From: Jordan Niethe Date: Wed, 6 May 2020 13:40:34 +1000 Subject: powerpc: Add a probe_kernel_read_inst() function Introduce a probe_kernel_read_inst() function to use in cases where probe_kernel_read() is used for getting an instruction. This will be more useful for prefixed instructions. Signed-off-by: Jordan Niethe Reviewed-by: Alistair Popple [mpe: Don't write to *inst on error] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200506034050.24806-15-jniethe5@gmail.com --- arch/powerpc/kernel/trace/ftrace.c | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-) (limited to 'arch/powerpc/kernel/trace') diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c index acd5b889815f..5e399628f51a 100644 --- a/arch/powerpc/kernel/trace/ftrace.c +++ b/arch/powerpc/kernel/trace/ftrace.c @@ -68,7 +68,7 @@ ftrace_modify_code(unsigned long ip, struct ppc_inst old, struct ppc_inst new) */ /* read the text we want to modify */ - if (probe_kernel_read(&replaced, (void *)ip, MCOUNT_INSN_SIZE)) + if (probe_kernel_read_inst(&replaced, (void *)ip)) return -EFAULT; /* Make sure it is what we expect it to be */ @@ -130,7 +130,7 @@ __ftrace_make_nop(struct module *mod, struct ppc_inst op, pop; /* read where this goes */ - if (probe_kernel_read(&op, (void *)ip, sizeof(int))) { + if (probe_kernel_read_inst(&op, (void *)ip)) { pr_err("Fetching opcode failed.\n"); return -EFAULT; } @@ -164,7 +164,7 @@ __ftrace_make_nop(struct module *mod, /* When using -mkernel_profile there is no load to jump over */ pop = ppc_inst(PPC_INST_NOP); - if (probe_kernel_read(&op, (void *)(ip - 4), 4)) { + if (probe_kernel_read_inst(&op, (void *)(ip - 4))) { pr_err("Fetching instruction at %lx failed.\n", ip - 4); return -EFAULT; } @@ -197,7 +197,7 @@ __ftrace_make_nop(struct module *mod, * Check what is in the next instruction. We can see ld r2,40(r1), but * on first pass after boot we will see mflr r0. */ - if (probe_kernel_read(&op, (void *)(ip+4), MCOUNT_INSN_SIZE)) { + if (probe_kernel_read_inst(&op, (void *)(ip + 4))) { pr_err("Fetching op failed.\n"); return -EFAULT; } @@ -349,7 +349,7 @@ static int setup_mcount_compiler_tramp(unsigned long tramp) return -1; /* New trampoline -- read where this goes */ - if (probe_kernel_read(&op, (void *)tramp, sizeof(int))) { + if (probe_kernel_read_inst(&op, (void *)tramp)) { pr_debug("Fetching opcode failed.\n"); return -1; } @@ -399,7 +399,7 @@ static int __ftrace_make_nop_kernel(struct dyn_ftrace *rec, unsigned long addr) struct ppc_inst op; /* Read where this goes */ - if (probe_kernel_read(&op, (void *)ip, sizeof(int))) { + if (probe_kernel_read_inst(&op, (void *)ip)) { pr_err("Fetching opcode failed.\n"); return -EFAULT; } @@ -526,7 +526,10 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) struct module *mod = rec->arch.mod; /* read where this goes */ - if (probe_kernel_read(op, ip, sizeof(op))) + if (probe_kernel_read_inst(op, ip)) + return -EFAULT; + + if (probe_kernel_read_inst(op + 1, ip + 4)) return -EFAULT; if (!expected_nop_sequence(ip, op[0], op[1])) { @@ -589,7 +592,7 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) unsigned long ip = rec->ip; /* read where this goes */ - if (probe_kernel_read(&op, (void *)ip, MCOUNT_INSN_SIZE)) + if (probe_kernel_read_inst(&op, (void *)ip)) return -EFAULT; /* It should be pointing to a nop */ @@ -645,7 +648,7 @@ static int __ftrace_make_call_kernel(struct dyn_ftrace *rec, unsigned long addr) } /* Make sure we have a nop */ - if (probe_kernel_read(&op, ip, sizeof(op))) { + if (probe_kernel_read_inst(&op, ip)) { pr_err("Unable to read ftrace location %p\n", ip); return -EFAULT; } @@ -723,7 +726,7 @@ __ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, } /* read where this goes */ - if (probe_kernel_read(&op, (void *)ip, sizeof(int))) { + if (probe_kernel_read_inst(&op, (void *)ip)) { pr_err("Fetching opcode failed.\n"); return -EFAULT; } -- cgit v1.2.3