[PATCH v2 19/25] powerpc/ftrace: Minimise number of #ifdefs

From: Christophe Leroy
Date: Sat May 07 2022 - 02:48:53 EST

A lot of #ifdefs can be replaced by IS_ENABLED()

Do so.

This requires to have kernel_toc_addr() defined at all time
as well as PPC_INST_LD_TOC and PPC_INST_STD_LR.

Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
---
v2: Moved the setup of pop outside of the big if()/else() in __ftrace_make_nop()
---
arch/powerpc/include/asm/code-patching.h | 2 -
arch/powerpc/include/asm/module.h | 2 -
arch/powerpc/include/asm/sections.h | 24 +--
arch/powerpc/kernel/trace/ftrace.c | 182 +++++++++++------------
4 files changed, 103 insertions(+), 107 deletions(-)

diff --git a/arch/powerpc/include/asm/code-patching.h b/arch/powerpc/include/asm/code-patching.h
index 8b1a10868275..3f881548fb61 100644
--- a/arch/powerpc/include/asm/code-patching.h
+++ b/arch/powerpc/include/asm/code-patching.h
@@ -217,7 +217,6 @@ static inline unsigned long ppc_kallsyms_lookup_name(const char *name)
return addr;
}

-#ifdef CONFIG_PPC64
/*
* Some instruction encodings commonly used in dynamic ftracing
* and function live patching.
@@ -234,6 +233,5 @@ static inline unsigned long ppc_kallsyms_lookup_name(const char *name)

/* usually preceded by a mflr r0 */
#define PPC_INST_STD_LR PPC_RAW_STD(_R0, _R1, PPC_LR_STKOFF)
-#endif /* CONFIG_PPC64 */

#endif /* _ASM_POWERPC_CODE_PATCHING_H */
diff --git a/arch/powerpc/include/asm/module.h b/arch/powerpc/include/asm/module.h
index 857d9ff24295..09e2ffd360bb 100644
--- a/arch/powerpc/include/asm/module.h
+++ b/arch/powerpc/include/asm/module.h
@@ -41,9 +41,7 @@ struct mod_arch_specific {

#ifdef CONFIG_DYNAMIC_FTRACE
unsigned long tramp;
-#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
unsigned long tramp_regs;
-#endif
#endif

/* List of BUG addresses, source line numbers and filenames */
diff --git a/arch/powerpc/include/asm/sections.h b/arch/powerpc/include/asm/sections.h
index 8be2c491c733..6980eaeb16fe 100644
--- a/arch/powerpc/include/asm/sections.h
+++ b/arch/powerpc/include/asm/sections.h
@@ -29,18 +29,6 @@ extern char start_virt_trampolines[];
extern char end_virt_trampolines[];
#endif

-/*
- * This assumes the kernel is never compiled -mcmodel=small or
- * the total .toc is always less than 64k.
- */
-static inline unsigned long kernel_toc_addr(void)
-{
- unsigned long toc_ptr;
-
- asm volatile("mr %0, 2" : "=r" (toc_ptr));
- return toc_ptr;
-}
-
static inline int overlaps_interrupt_vector_text(unsigned long start,
unsigned long end)
{
@@ -60,5 +48,17 @@ static inline int overlaps_kernel_text(unsigned long start, unsigned long end)

#endif

+/*
+ * This assumes the kernel is never compiled -mcmodel=small or
+ * the total .toc is always less than 64k.
+ */
+static inline unsigned long kernel_toc_addr(void)
+{
+ unsigned long toc_ptr;
+
+ asm volatile("mr %0, 2" : "=r" (toc_ptr));
+ return toc_ptr;
+}
+
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_SECTIONS_H */
diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c
index c34cb394f8a8..5e7a4ed7ad22 100644
--- a/arch/powerpc/kernel/trace/ftrace.c
+++ b/arch/powerpc/kernel/trace/ftrace.c
@@ -150,26 +150,39 @@ __ftrace_make_nop(struct module *mod,
return -EINVAL;
}

- /* When using -mprofile-kernel or PPC32 there is no load to jump over */
- pop = ppc_inst(PPC_RAW_NOP());
+ if (IS_ENABLED(CONFIG_MPROFILE_KERNEL)) {
+ if (copy_inst_from_kernel_nofault(&op, (void *)(ip - 4))) {
+ pr_err("Fetching instruction at %lx failed.\n", ip - 4);
+ return -EFAULT;
+ }

-#ifdef CONFIG_PPC64
-#ifdef CONFIG_MPROFILE_KERNEL
- if (copy_inst_from_kernel_nofault(&op, (void *)(ip - 4))) {
- pr_err("Fetching instruction at %lx failed.\n", ip - 4);
- return -EFAULT;
- }
+ /* We expect either a mflr r0, or a std r0, LRSAVE(r1) */
+ if (!ppc_inst_equal(op, ppc_inst(PPC_RAW_MFLR(_R0))) &&
+ !ppc_inst_equal(op, ppc_inst(PPC_INST_STD_LR))) {
+ pr_err("Unexpected instruction %s around bl _mcount\n",
+ ppc_inst_as_str(op));
+ return -EINVAL;
+ }
+ } else if (IS_ENABLED(CONFIG_PPC64)) {
+ /*
+ * 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 (copy_inst_from_kernel_nofault(&op, (void *)(ip + 4))) {
+ pr_err("Fetching op failed.\n");
+ return -EFAULT;
+ }

- /* We expect either a mflr r0, or a std r0, LRSAVE(r1) */
- if (!ppc_inst_equal(op, ppc_inst(PPC_RAW_MFLR(_R0))) &&
- !ppc_inst_equal(op, ppc_inst(PPC_INST_STD_LR))) {
- pr_err("Unexpected instruction %s around bl _mcount\n",
- ppc_inst_as_str(op));
- return -EINVAL;
+ if (!ppc_inst_equal(op, ppc_inst(PPC_INST_LD_TOC))) {
+ pr_err("Expected %08lx found %s\n", PPC_INST_LD_TOC, ppc_inst_as_str(op));
+ return -EINVAL;
+ }
}
-#else
+
/*
- * Our original call site looks like:
+ * When using -mprofile-kernel or PPC32 there is no load to jump over.
+ *
+ * Otherwise our original call site looks like:
*
* bl <tramp>
* ld r2,XX(r1)
@@ -181,24 +194,10 @@ __ftrace_make_nop(struct module *mod,
*
* Use a b +8 to jump over the load.
*/
-
- pop = ppc_inst(PPC_RAW_BRANCH(8)); /* b +8 */
-
- /*
- * 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 (copy_inst_from_kernel_nofault(&op, (void *)(ip + 4))) {
- pr_err("Fetching op failed.\n");
- return -EFAULT;
- }
-
- if (!ppc_inst_equal(op, ppc_inst(PPC_INST_LD_TOC))) {
- pr_err("Expected %08lx found %s\n", PPC_INST_LD_TOC, ppc_inst_as_str(op));
- return -EINVAL;
- }
-#endif /* CONFIG_MPROFILE_KERNEL */
-#endif /* PPC64 */
+ if (IS_ENABLED(CONFIG_MPROFILE_KERNEL) || IS_ENABLED(CONFIG_PPC32))
+ pop = ppc_inst(PPC_RAW_NOP());
+ else
+ pop = ppc_inst(PPC_RAW_BRANCH(8)); /* b +8 */

if (patch_instruction((u32 *)ip, pop)) {
pr_err("Patching NOP failed.\n");
@@ -207,6 +206,11 @@ __ftrace_make_nop(struct module *mod,

return 0;
}
+#else
+static int __ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr)
+{
+ return 0;
+}
#endif /* CONFIG_MODULES */

static unsigned long find_ftrace_tramp(unsigned long ip)
@@ -279,11 +283,11 @@ static int setup_mcount_compiler_tramp(unsigned long tramp)
}

/* Let's re-write the tramp to go to ftrace_[regs_]caller */
-#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
- ptr = ppc_global_function_entry((void *)ftrace_regs_caller);
-#else
- ptr = ppc_global_function_entry((void *)ftrace_caller);
-#endif
+ if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS))
+ ptr = ppc_global_function_entry((void *)ftrace_regs_caller);
+ else
+ ptr = ppc_global_function_entry((void *)ftrace_caller);
+
if (patch_branch((u32 *)tramp, ptr, 0)) {
pr_debug("REL24 out of range!\n");
return -1;
@@ -352,10 +356,12 @@ int ftrace_make_nop(struct module *mod,
old = ftrace_call_replace(ip, addr, 1);
new = ppc_inst(PPC_RAW_NOP());
return ftrace_modify_code(ip, old, new);
- } else if (core_kernel_text(ip))
+ } else if (core_kernel_text(ip)) {
return __ftrace_make_nop_kernel(rec, addr);
+ } else if (!IS_ENABLED(CONFIG_MODULES)) {
+ return -EINVAL;
+ }

-#ifdef CONFIG_MODULES
/*
* Out of range jumps are called from modules.
* We should either already have a pointer to the module
@@ -378,10 +384,6 @@ int ftrace_make_nop(struct module *mod,
mod = rec->arch.mod;

return __ftrace_make_nop(mod, rec, addr);
-#else
- /* We should not get here without modules */
- return -EINVAL;
-#endif /* CONFIG_MODULES */
}

#ifdef CONFIG_MODULES
@@ -411,10 +413,9 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
if (copy_inst_from_kernel_nofault(op, ip))
return -EFAULT;

-#ifdef CONFIG_PPC64_ELF_ABI_V1
- if (copy_inst_from_kernel_nofault(op + 1, ip + 4))
+ if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V1) &&
+ copy_inst_from_kernel_nofault(op + 1, ip + 4))
return -EFAULT;
-#endif

if (!expected_nop_sequence(ip, op[0], op[1])) {
pr_err("Unexpected call sequence at %p: %s %s\n",
@@ -423,20 +424,15 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
}

/* If we never set up ftrace trampoline(s), then bail */
-#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
- if (!mod->arch.tramp || !mod->arch.tramp_regs) {
-#else
- if (!mod->arch.tramp) {
-#endif
+ if (!mod->arch.tramp ||
+ (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && !mod->arch.tramp_regs)) {
pr_err("No ftrace trampoline\n");
return -EINVAL;
}

-#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
- if (rec->flags & FTRACE_FL_REGS)
+ if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && rec->flags & FTRACE_FL_REGS)
tramp = mod->arch.tramp_regs;
else
-#endif
tramp = mod->arch.tramp;

if (module_trampoline_target(mod, tramp, &ptr)) {
@@ -460,6 +456,11 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)

return 0;
}
+#else
+static int __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
+{
+ return 0;
+}
#endif /* CONFIG_MODULES */

static int __ftrace_make_call_kernel(struct dyn_ftrace *rec, unsigned long addr)
@@ -472,16 +473,12 @@ static int __ftrace_make_call_kernel(struct dyn_ftrace *rec, unsigned long addr)
entry = ppc_global_function_entry((void *)ftrace_caller);
ptr = ppc_global_function_entry((void *)addr);

- if (ptr != entry) {
-#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
+ if (ptr != entry && IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS))
entry = ppc_global_function_entry((void *)ftrace_regs_caller);
- if (ptr != entry) {
-#endif
- pr_err("Unknown ftrace addr to patch: %ps\n", (void *)ptr);
- return -EINVAL;
-#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
- }
-#endif
+
+ if (ptr != entry) {
+ pr_err("Unknown ftrace addr to patch: %ps\n", (void *)ptr);
+ return -EINVAL;
}

/* Make sure we have a nop */
@@ -524,10 +521,13 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
old = ppc_inst(PPC_RAW_NOP());
new = ftrace_call_replace(ip, addr, 1);
return ftrace_modify_code(ip, old, new);
- } else if (core_kernel_text(ip))
+ } else if (core_kernel_text(ip)) {
return __ftrace_make_call_kernel(rec, addr);
+ } else if (!IS_ENABLED(CONFIG_MODULES)) {
+ /* We should not get here without modules */
+ return -EINVAL;
+ }

-#ifdef CONFIG_MODULES
/*
* Out of range jumps are called from modules.
* Being that we are converting from nop, it had better
@@ -539,10 +539,6 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
}

return __ftrace_make_call(rec, addr);
-#else
- /* We should not get here without modules */
- return -EINVAL;
-#endif /* CONFIG_MODULES */
}

#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
@@ -633,6 +629,11 @@ __ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,

return 0;
}
+#else
+static int __ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, unsigned long addr)
+{
+ return 0;
+}
#endif

int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
@@ -657,9 +658,11 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
* variant, so there is nothing to do here
*/
return 0;
+ } else if (!IS_ENABLED(CONFIG_MODULES)) {
+ /* We should not get here without modules */
+ return -EINVAL;
}

-#ifdef CONFIG_MODULES
/*
* Out of range jumps are called from modules.
*/
@@ -669,10 +672,6 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
}

return __ftrace_modify_call(rec, old_addr, addr);
-#else
- /* We should not get here without modules */
- return -EINVAL;
-#endif /* CONFIG_MODULES */
}
#endif

@@ -686,15 +685,13 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
new = ftrace_call_replace(ip, (unsigned long)func, 1);
ret = ftrace_modify_code(ip, old, new);

-#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
/* Also update the regs callback function */
- if (!ret) {
+ if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && !ret) {
ip = (unsigned long)(&ftrace_regs_call);
old = ppc_inst_read((u32 *)&ftrace_regs_call);
new = ftrace_call_replace(ip, (unsigned long)func, 1);
ret = ftrace_modify_code(ip, old, new);
}
-#endif

return ret;
}
@@ -710,6 +707,9 @@ void arch_ftrace_update_code(int command)

#ifdef CONFIG_PPC64
#define PACATOC offsetof(struct paca_struct, kernel_toc)
+#else
+#define PACATOC 0
+#endif

extern unsigned int ftrace_tramp_text[], ftrace_tramp_init[];

@@ -724,12 +724,18 @@ int __init ftrace_dyn_arch_init(void)
PPC_RAW_MTCTR(_R12),
PPC_RAW_BCTR()
};
-#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
- unsigned long addr = ppc_global_function_entry((void *)ftrace_regs_caller);
-#else
- unsigned long addr = ppc_global_function_entry((void *)ftrace_caller);
-#endif
- long reladdr = addr - kernel_toc_addr();
+ unsigned long addr;
+ long reladdr;
+
+ if (IS_ENABLED(CONFIG_PPC32))
+ return 0;
+
+ if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS))
+ addr = ppc_global_function_entry((void *)ftrace_regs_caller);
+ else
+ addr = ppc_global_function_entry((void *)ftrace_caller);
+
+ reladdr = addr - kernel_toc_addr();

if (reladdr >= SZ_2G || reladdr < -SZ_2G) {
pr_err("Address of %ps out of range of kernel_toc.\n",
@@ -746,12 +752,6 @@ int __init ftrace_dyn_arch_init(void)

return 0;
}
-#else
-int __init ftrace_dyn_arch_init(void)
-{
- return 0;
-}
-#endif

#ifdef CONFIG_FUNCTION_GRAPH_TRACER

--
2.35.1