@@ -7,7 +7,19 @@
#ifndef __ASSEMBLY__
extern void _mcount(void);
-#endif
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+static inline unsigned long ftrace_call_adjust(unsigned long addr)
+{
+ /* reloction of mcount call site is the same as the address */
+ return addr;
+}
+
+struct dyn_arch_ftrace {
+ struct module *mod;
+};
+#endif /* CONFIG_DYNAMIC_FTRACE */
+#endif /* __ASSEMBLY__ */
#endif
@@ -34,11 +34,19 @@ struct mod_arch_specific {
#ifdef __powerpc64__
unsigned int stubs_section; /* Index of stubs section in module */
unsigned int toc_section; /* What section is the TOC? */
-#else
+#ifdef CONFIG_DYNAMIC_FTRACE
+ unsigned long toc;
+ unsigned long tramp;
+#endif
+
+#else /* powerpc64 */
/* Indices of PLT sections within module. */
unsigned int core_plt_section;
unsigned int init_plt_section;
+#ifdef CONFIG_DYNAMIC_FTRACE
+ unsigned long tramp;
#endif
+#endif /* powerpc64 */
/* List of BUG addresses, source line numbers and filenames */
struct list_head bug_list;
@@ -68,6 +76,12 @@ struct mod_arch_specific {
# endif /* MODULE */
#endif
+#ifdef CONFIG_DYNAMIC_FTRACE
+# ifdef MODULE
+ asm(".section .ftrace.tramp,\"ax\",@nobits; .align 3; .previous");
+# endif /* MODULE */
+#endif
+
struct exception_table_entry;
void sort_ex_table(struct exception_table_entry *start,
@@ -17,6 +17,7 @@ ifdef CONFIG_FUNCTION_TRACER
CFLAGS_REMOVE_cputable.o = -pg -mno-sched-epilog
CFLAGS_REMOVE_prom_init.o = -pg -mno-sched-epilog
CFLAGS_REMOVE_btext.o = -pg -mno-sched-epilog
+CFLAGS_REMOVE_prom.o = -pg -mno-sched-epilog
ifdef CONFIG_DYNAMIC_FTRACE
# dynamic ftrace setup.
@@ -1162,39 +1162,17 @@ machine_check_in_rtas:
#ifdef CONFIG_DYNAMIC_FTRACE
_GLOBAL(mcount)
_GLOBAL(_mcount)
- stwu r1,-48(r1)
- stw r3, 12(r1)
- stw r4, 16(r1)
- stw r5, 20(r1)
- stw r6, 24(r1)
- mflr r3
- stw r7, 28(r1)
- mfcr r5
- stw r8, 32(r1)
- stw r9, 36(r1)
- stw r10,40(r1)
- stw r3, 44(r1)
- stw r5, 8(r1)
- subi r3, r3, MCOUNT_INSN_SIZE
- .globl mcount_call
-mcount_call:
- bl ftrace_stub
- nop
- lwz r6, 8(r1)
- lwz r0, 44(r1)
- lwz r3, 12(r1)
+ /*
+ * It is required that _mcount on PPC32 must preserve the
+ * link register. But we have r0 to play with. We use r0
+ * to push the return address back to the caller of mcount
+ * into the ctr register, restore the link register and
+ * then jump back using the ctr register.
+ */
+ mflr r0
mtctr r0
- lwz r4, 16(r1)
- mtcr r6
- lwz r5, 20(r1)
- lwz r6, 24(r1)
- lwz r0, 52(r1)
- lwz r7, 28(r1)
- lwz r8, 32(r1)
+ lwz r0, 4(r1)
mtlr r0
- lwz r9, 36(r1)
- lwz r10,40(r1)
- addi r1, r1, 48
bctr
_GLOBAL(ftrace_caller)
@@ -888,18 +888,6 @@ _GLOBAL(enter_prom)
#ifdef CONFIG_DYNAMIC_FTRACE
_GLOBAL(mcount)
_GLOBAL(_mcount)
- /* Taken from output of objdump from lib64/glibc */
- mflr r3
- stdu r1, -112(r1)
- std r3, 128(r1)
- subi r3, r3, MCOUNT_INSN_SIZE
- .globl mcount_call
-mcount_call:
- bl ftrace_stub
- nop
- ld r0, 128(r1)
- mtlr r0
- addi r1, r1, 112
blr
_GLOBAL(ftrace_caller)
@@ -9,22 +9,30 @@
#include <linux/spinlock.h>
#include <linux/hardirq.h>
+#include <linux/uaccess.h>
+#include <linux/module.h>
#include <linux/ftrace.h>
#include <linux/percpu.h>
#include <linux/init.h>
#include <linux/list.h>
#include <asm/cacheflush.h>
+#include <asm/code-patching.h>
#include <asm/ftrace.h>
+#if 0
+#define DEBUGP printk
+#else
+#define DEBUGP(fmt , ...) do { } while (0)
+#endif
-static unsigned int ftrace_nop = 0x60000000;
+static unsigned int ftrace_nop = PPC_NOP_INSTR;
#ifdef CONFIG_PPC32
# define GET_ADDR(addr) addr
#else
/* PowerPC64's functions are data that points to the functions */
-# define GET_ADDR(addr) *(unsigned long *)addr
+# define GET_ADDR(addr) (*(unsigned long *)addr)
#endif
@@ -33,12 +41,12 @@ static unsigned int ftrace_calc_offset(long ip, long addr)
return (int)(addr - ip);
}
-unsigned char *ftrace_nop_replace(void)
+static unsigned char *ftrace_nop_replace(void)
{
return (char *)&ftrace_nop;
}
-unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
+static unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
{
static unsigned int op;
@@ -68,49 +76,422 @@ unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
# define _ASM_PTR " .long "
#endif
-int
+static int
ftrace_modify_code(unsigned long ip, unsigned char *old_code,
unsigned char *new_code)
{
- unsigned replaced;
- unsigned old = *(unsigned *)old_code;
- unsigned new = *(unsigned *)new_code;
- int faulted = 0;
+ unsigned char replaced[MCOUNT_INSN_SIZE];
/*
* Note: Due to modules and __init, code can
* disappear and change, we need to protect against faulting
- * as well as code changing.
+ * as well as code changing. We do this by using the
+ * probe_kernel_* functions.
*
* No real locking needed, this code is run through
- * kstop_machine.
+ * kstop_machine, or before SMP starts.
*/
- asm volatile (
- "1: lwz %1, 0(%2)\n"
- " cmpw %1, %5\n"
- " bne 2f\n"
- " stwu %3, 0(%2)\n"
- "2:\n"
- ".section .fixup, \"ax\"\n"
- "3: li %0, 1\n"
- " b 2b\n"
- ".previous\n"
- ".section __ex_table,\"a\"\n"
- _ASM_ALIGN "\n"
- _ASM_PTR "1b, 3b\n"
- ".previous"
- : "=r"(faulted), "=r"(replaced)
- : "r"(ip), "r"(new),
- "0"(faulted), "r"(old)
- : "memory");
-
- if (replaced != old && replaced != new)
- faulted = 2;
-
- if (!faulted)
- flush_icache_range(ip, ip + 8);
-
- return faulted;
+
+ /* read the text we want to modify */
+ if (probe_kernel_read(replaced, (void *)ip, MCOUNT_INSN_SIZE))
+ return -EFAULT;
+
+ /* Make sure it is what we expect it to be */
+ if (memcmp(replaced, old_code, MCOUNT_INSN_SIZE) != 0)
+ return -EINVAL;
+
+ /* replace the text with the new text */
+ if (probe_kernel_write((void *)ip, new_code, MCOUNT_INSN_SIZE))
+ return -EPERM;
+
+ flush_icache_range(ip, ip + 8);
+
+ return 0;
+}
+
+/*
+ * Helper functions that are the same for both PPC64 and PPC32.
+ */
+static int test_24bit_addr(unsigned long ip, unsigned long addr)
+{
+
+ /* use the create_branch to verify that this offset can be branched */
+ return create_branch((unsigned int *)ip, addr, 0);
+}
+
+static int is_bl_op(unsigned int op)
+{
+ return (op & 0xfc000003) == 0x48000001;
+}
+
+static unsigned long find_bl_target(unsigned long ip, unsigned int op)
+{
+ static int offset;
+
+ offset = (op & 0x03fffffc);
+ /* make it signed */
+ if (offset & 0x02000000)
+ offset |= 0xfe000000;
+
+ return ip + (long)offset;
+}
+
+#ifdef CONFIG_PPC64
+static int
+__ftrace_make_nop(struct module *mod,
+ struct dyn_ftrace *rec, unsigned long addr)
+{
+ unsigned int op;
+ unsigned int jmp[5];
+ unsigned long ptr;
+ unsigned long ip = rec->ip;
+ unsigned long tramp;
+ int offset;
+
+ /* read where this goes */
+ if (probe_kernel_read(&op, (void *)ip, sizeof(int)))
+ return -EFAULT;
+
+ /* Make sure that that this is still a 24bit jump */
+ if (!is_bl_op(op)) {
+ printk(KERN_ERR "Not expected bl: opcode is %x\n", op);
+ return -EINVAL;
+ }
+
+ /* lets find where the pointer goes */
+ tramp = find_bl_target(ip, op);
+
+ /*
+ * On PPC64 the trampoline looks like:
+ * 0x3d, 0x82, 0x00, 0x00, addis r12,r2, <high>
+ * 0x39, 0x8c, 0x00, 0x00, addi r12,r12, <low>
+ * Where the bytes 2,3,6 and 7 make up the 32bit offset
+ * to the TOC that holds the pointer.
+ * to jump to.
+ * 0xf8, 0x41, 0x00, 0x28, std r2,40(r1)
+ * 0xe9, 0x6c, 0x00, 0x20, ld r11,32(r12)
+ * The actually address is 32 bytes from the offset
+ * into the TOC.
+ * 0xe8, 0x4c, 0x00, 0x28, ld r2,40(r12)
+ */
+
+ DEBUGP("ip:%lx jumps to %lx r2: %lx", ip, tramp, mod->arch.toc);
+
+ /* Find where the trampoline jumps to */
+ if (probe_kernel_read(jmp, (void *)tramp, sizeof(jmp))) {
+ printk(KERN_ERR "Failed to read %lx\n", tramp);
+ return -EFAULT;
+ }
+
+ DEBUGP(" %08x %08x", jmp[0], jmp[1]);
+
+ /* verify that this is what we expect it to be */
+ if (((jmp[0] & 0xffff0000) != 0x3d820000) ||
+ ((jmp[1] & 0xffff0000) != 0x398c0000) ||
+ (jmp[2] != 0xf8410028) ||
+ (jmp[3] != 0xe96c0020) ||
+ (jmp[4] != 0xe84c0028)) {
+ printk(KERN_ERR "Not a trampoline\n");
+ return -EINVAL;
+ }
+
+ offset = (unsigned)((unsigned short)jmp[0]) << 16 |
+ (unsigned)((unsigned short)jmp[1]);
+
+ DEBUGP(" %x ", offset);
+
+ /* get the address this jumps too */
+ tramp = mod->arch.toc + offset + 32;
+ DEBUGP("toc: %lx", tramp);
+
+ if (probe_kernel_read(jmp, (void *)tramp, 8)) {
+ printk(KERN_ERR "Failed to read %lx\n", tramp);
+ return -EFAULT;
+ }
+
+ DEBUGP(" %08x %08x\n", jmp[0], jmp[1]);
+
+ ptr = ((unsigned long)jmp[0] << 32) + jmp[1];
+
+ /* This should match what was called */
+ if (ptr != GET_ADDR(addr)) {
+ printk(KERN_ERR "addr does not match %lx\n", ptr);
+ return -EINVAL;
+ }
+
+ /*
+ * We want to nop the line, but the next line is
+ * 0xe8, 0x41, 0x00, 0x28 ld r2,40(r1)
+ * This needs to be turned to a nop too.
+ */
+ if (probe_kernel_read(&op, (void *)(ip+4), MCOUNT_INSN_SIZE))
+ return -EFAULT;
+
+ if (op != 0xe8410028) {
+ printk(KERN_ERR "Next line is not ld! (%08x)\n", op);
+ return -EINVAL;
+ }
+
+ /*
+ * Milton Miller pointed out that we can not blindly do nops.
+ * If a task was preempted when calling a trace function,
+ * the nops will remove the way to restore the TOC in r2
+ * and the r2 TOC will get corrupted.
+ */
+
+ /*
+ * Replace:
+ * bl <tramp> <==== will be replaced with "b 1f"
+ * ld r2,40(r1)
+ * 1:
+ */
+ op = 0x48000008; /* b +8 */
+
+ if (probe_kernel_write((void *)ip, &op, MCOUNT_INSN_SIZE))
+ return -EPERM;
+
+
+ flush_icache_range(ip, ip + 8);
+
+ return 0;
+}
+
+#else /* !PPC64 */
+static int
+__ftrace_make_nop(struct module *mod,
+ struct dyn_ftrace *rec, unsigned long addr)
+{
+ unsigned int op;
+ unsigned int jmp[4];
+ unsigned long ip = rec->ip;
+ unsigned long tramp;
+
+ if (probe_kernel_read(&op, (void *)ip, MCOUNT_INSN_SIZE))
+ return -EFAULT;
+
+ /* Make sure that that this is still a 24bit jump */
+ if (!is_bl_op(op)) {
+ printk(KERN_ERR "Not expected bl: opcode is %x\n", op);
+ return -EINVAL;
+ }
+
+ /* lets find where the pointer goes */
+ tramp = find_bl_target(ip, op);
+
+ /*
+ * On PPC32 the trampoline looks like:
+ * 0x3d, 0x60, 0x00, 0x00 lis r11,sym@ha
+ * 0x39, 0x6b, 0x00, 0x00 addi r11,r11,sym@l
+ * 0x7d, 0x69, 0x03, 0xa6 mtctr r11
+ * 0x4e, 0x80, 0x04, 0x20 bctr
+ */
+
+ DEBUGP("ip:%lx jumps to %lx", ip, tramp);
+
+ /* Find where the trampoline jumps to */
+ if (probe_kernel_read(jmp, (void *)tramp, sizeof(jmp))) {
+ printk(KERN_ERR "Failed to read %lx\n", tramp);
+ return -EFAULT;
+ }
+
+ DEBUGP(" %08x %08x ", jmp[0], jmp[1]);
+
+ /* verify that this is what we expect it to be */
+ if (((jmp[0] & 0xffff0000) != 0x3d600000) ||
+ ((jmp[1] & 0xffff0000) != 0x396b0000) ||
+ (jmp[2] != 0x7d6903a6) ||
+ (jmp[3] != 0x4e800420)) {
+ printk(KERN_ERR "Not a trampoline\n");
+ return -EINVAL;
+ }
+
+ tramp = (jmp[1] & 0xffff) |
+ ((jmp[0] & 0xffff) << 16);
+ if (tramp & 0x8000)
+ tramp -= 0x10000;
+
+ DEBUGP(" %x ", tramp);
+
+ if (tramp != addr) {
+ printk(KERN_ERR
+ "Trampoline location %08lx does not match addr\n",
+ tramp);
+ return -EINVAL;
+ }
+
+ op = PPC_NOP_INSTR;
+
+ if (probe_kernel_write((void *)ip, &op, MCOUNT_INSN_SIZE))
+ return -EPERM;
+
+ flush_icache_range(ip, ip + 8);
+
+ return 0;
+}
+#endif /* PPC64 */
+
+int ftrace_make_nop(struct module *mod,
+ struct dyn_ftrace *rec, unsigned long addr)
+{
+ unsigned char *old, *new;
+ unsigned long ip = rec->ip;
+
+ /*
+ * If the calling address is more that 24 bits away,
+ * then we had to use a trampoline to make the call.
+ * Otherwise just update the call site.
+ */
+ if (test_24bit_addr(ip, addr)) {
+ /* within range */
+ old = ftrace_call_replace(ip, addr);
+ new = ftrace_nop_replace();
+ return ftrace_modify_code(ip, old, new);
+ }
+
+ /*
+ * Out of range jumps are called from modules.
+ * We should either already have a pointer to the module
+ * or it has been passed in.
+ */
+ if (!rec->arch.mod) {
+ if (!mod) {
+ printk(KERN_ERR "No module loaded addr=%lx\n",
+ addr);
+ return -EFAULT;
+ }
+ rec->arch.mod = mod;
+ } else if (mod) {
+ if (mod != rec->arch.mod) {
+ printk(KERN_ERR
+ "Record mod %p not equal to passed in mod %p\n",
+ rec->arch.mod, mod);
+ return -EINVAL;
+ }
+ /* nothing to do if mod == rec->arch.mod */
+ } else
+ mod = rec->arch.mod;
+
+ return __ftrace_make_nop(mod, rec, addr);
+
+}
+
+#ifdef CONFIG_PPC64
+static int
+__ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
+{
+ unsigned int op[2];
+ unsigned long ip = rec->ip;
+
+ /* read where this goes */
+ if (probe_kernel_read(op, (void *)ip, MCOUNT_INSN_SIZE * 2))
+ return -EFAULT;
+
+ /*
+ * It should be pointing to two nops or
+ * b +8; ld r2,40(r1)
+ */
+ if (((op[0] != 0x48000008) || (op[1] != 0xe8410028)) &&
+ ((op[0] != PPC_NOP_INSTR) || (op[1] != PPC_NOP_INSTR))) {
+ printk(KERN_ERR "Expected NOPs but have %x %x\n", op[0], op[1]);
+ return -EINVAL;
+ }
+
+ /* If we never set up a trampoline to ftrace_caller, then bail */
+ if (!rec->arch.mod->arch.tramp) {
+ printk(KERN_ERR "No ftrace trampoline\n");
+ return -EINVAL;
+ }
+
+ /* create the branch to the trampoline */
+ op[0] = create_branch((unsigned int *)ip,
+ rec->arch.mod->arch.tramp, BRANCH_SET_LINK);
+ if (!op[0]) {
+ printk(KERN_ERR "REL24 out of range!\n");
+ return -EINVAL;
+ }
+
+ /* ld r2,40(r1) */
+ op[1] = 0xe8410028;
+
+ DEBUGP("write to %lx\n", rec->ip);
+
+ if (probe_kernel_write((void *)ip, op, MCOUNT_INSN_SIZE * 2))
+ return -EPERM;
+
+ flush_icache_range(ip, ip + 8);
+
+ return 0;
+}
+#else
+static int
+__ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
+{
+ unsigned int op;
+ unsigned long ip = rec->ip;
+
+ /* read where this goes */
+ if (probe_kernel_read(&op, (void *)ip, MCOUNT_INSN_SIZE))
+ return -EFAULT;
+
+ /* It should be pointing to a nop */
+ if (op != PPC_NOP_INSTR) {
+ printk(KERN_ERR "Expected NOP but have %x\n", op);
+ return -EINVAL;
+ }
+
+ /* If we never set up a trampoline to ftrace_caller, then bail */
+ if (!rec->arch.mod->arch.tramp) {
+ printk(KERN_ERR "No ftrace trampoline\n");
+ return -EINVAL;
+ }
+
+ /* create the branch to the trampoline */
+ op = create_branch((unsigned int *)ip,
+ rec->arch.mod->arch.tramp, BRANCH_SET_LINK);
+ if (!op) {
+ printk(KERN_ERR "REL24 out of range!\n");
+ return -EINVAL;
+ }
+
+ DEBUGP("write to %lx\n", rec->ip);
+
+ if (probe_kernel_write((void *)ip, &op, MCOUNT_INSN_SIZE))
+ return -EPERM;
+
+ flush_icache_range(ip, ip + 8);
+
+ return 0;
+}
+#endif /* CONFIG_PPC64 */
+
+int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
+{
+ unsigned char *old, *new;
+ unsigned long ip = rec->ip;
+
+ /*
+ * If the calling address is more that 24 bits away,
+ * then we had to use a trampoline to make the call.
+ * Otherwise just update the call site.
+ */
+ if (test_24bit_addr(ip, addr)) {
+ /* within range */
+ old = ftrace_nop_replace();
+ new = ftrace_call_replace(ip, addr);
+ return ftrace_modify_code(ip, old, new);
+ }
+
+ /*
+ * Out of range jumps are called from modules.
+ * Being that we are converting from nop, it had better
+ * already have a module defined.
+ */
+ if (!rec->arch.mod) {
+ printk(KERN_ERR "No module loaded\n");
+ return -EINVAL;
+ }
+
+ return __ftrace_make_call(rec, addr);
}
int ftrace_update_ftrace_func(ftrace_func_t func)
@@ -128,10 +509,10 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
int __init ftrace_dyn_arch_init(void *data)
{
- /* This is running in kstop_machine */
+ /* caller expects data to be zero */
+ unsigned long *p = data;
- ftrace_mcount_set(data);
+ *p = 0;
return 0;
}
-
@@ -69,10 +69,15 @@ void cpu_idle(void)
smp_mb();
local_irq_disable();
+ /* Don't trace irqs off for idle */
+ stop_critical_timings();
+
/* check again after disabling irqs */
if (!need_resched() && !cpu_should_die())
ppc_md.power_save();
+ start_critical_timings();
+
local_irq_enable();
set_thread_flag(TIF_POLLING_NRFLAG);
@@ -22,6 +22,7 @@
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/kernel.h>
+#include <linux/ftrace.h>
#include <linux/cache.h>
#include <linux/bug.h>
#include <linux/sort.h>
@@ -53,6 +54,9 @@ static unsigned int count_relocs(const Elf32_Rela *rela, unsigned int num)
r_addend = rela[i].r_addend;
}
+#ifdef CONFIG_DYNAMIC_FTRACE
+ _count_relocs++; /* add one for ftrace_caller */
+#endif
return _count_relocs;
}
@@ -306,5 +310,11 @@ int apply_relocate_add(Elf32_Shdr *sechdrs,
return -ENOEXEC;
}
}
+#ifdef CONFIG_DYNAMIC_FTRACE
+ module->arch.tramp =
+ do_plt_call(module->module_core,
+ (unsigned long)ftrace_caller,
+ sechdrs, module);
+#endif
return 0;
}
@@ -20,6 +20,7 @@
#include <linux/moduleloader.h>
#include <linux/err.h>
#include <linux/vmalloc.h>
+#include <linux/ftrace.h>
#include <linux/bug.h>
#include <asm/module.h>
#include <asm/firmware.h>
@@ -163,6 +164,11 @@ static unsigned long get_stubs_size(const Elf64_Ehdr *hdr,
}
}
+#ifdef CONFIG_DYNAMIC_FTRACE
+ /* make the trampoline to the ftrace_caller */
+ relocs++;
+#endif
+
DEBUGP("Looks like a total of %lu stubs, max\n", relocs);
return relocs * sizeof(struct ppc64_stub_entry);
}
@@ -441,5 +447,12 @@ int apply_relocate_add(Elf64_Shdr *sechdrs,
}
}
+#ifdef CONFIG_DYNAMIC_FTRACE
+ me->arch.toc = my_r2(sechdrs, me);
+ me->arch.tramp = stub_for_addr(sechdrs,
+ (unsigned long)ftrace_caller,
+ me);
+#endif
+
return 0;
}
@@ -6,6 +6,9 @@ ifeq ($(CONFIG_PPC64),y)
EXTRA_CFLAGS += -mno-minimal-toc
endif
+CFLAGS_REMOVE_code-patching.o = -pg
+CFLAGS_REMOVE_feature-fixups.o = -pg
+
obj-y := string.o alloc.o \
checksum_$(CONFIG_WORD_SIZE).o
obj-$(CONFIG_PPC32) += div64.o copy_32.o crtsavres.o