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Commit 813b8520 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

Merge branch 'ppc/ftrace' of... 

Merge branch 'ppc/ftrace' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into tracing/powerpc
parents ed313489 7cc45e64

arch/powerpc/include/asm/ftrace.h

+13 −1
Original line number Diff line number Diff line
@@ -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

arch/powerpc/include/asm/module.h

+15 −1
Original line number Diff line number Diff line
@@ -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,

arch/powerpc/kernel/ftrace.c

+433 −40
Original line number Diff line number Diff line
@@ -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 +76,434 @@ 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.

	 */

	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)

	 * kstop_machine, or before SMP starts.

	 */



	/* 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 faulted;

	return 0;

}



/*

 * Helper functions that are the same for both PPC64 and PPC32.

 */

static int test_24bit_addr(unsigned long ip, unsigned long addr)

{

	long diff;



	/*

	 * Can we get to addr from ip in 24 bits?

	 *  (26 really, since we mulitply by 4 for 4 byte alignment)

	 */

	diff = addr - ip;



	/*

	 * Return true if diff is less than 1 << 25

	 *  and greater than -1 << 26.

	 */

	return (diff < (1 << 25)) && (diff > (-1 << 26));

}



static int is_bl_op(unsigned int op)

{

	return (op & 0xfc000003) == 0x48000001;

}



static int test_offset(unsigned long offset)

{

	return (offset + 0x2000000 > 0x3ffffff) || ((offset & 3) != 0);

}



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;

}



static unsigned int branch_offset(unsigned long offset)

{

	/* return "bl ip+offset" */

	return 0x48000001 | (offset & 0x03fffffc);

}



#ifdef CONFIG_PPC64

static int

__ftrace_make_nop(struct module *mod,

		  struct dyn_ftrace *rec, unsigned long addr)

{

	unsigned char replaced[MCOUNT_INSN_SIZE * 2];

	unsigned int *op = (unsigned *)&replaced;

	unsigned char jmp[8];

	unsigned long *ptr = (unsigned long *)&jmp;

	unsigned long ip = rec->ip;

	unsigned long tramp;

	int offset;



	/* read where this goes */

	if (probe_kernel_read(replaced, (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 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, 8)) {

		printk(KERN_ERR "Failed to read %lx\n", tramp);

		return -EFAULT;

	}



	DEBUGP(" %08x %08x",

	       (unsigned)(*ptr >> 32),

	       (unsigned)*ptr);



	offset = (unsigned)jmp[2] << 24 |

		(unsigned)jmp[3] << 16 |

		(unsigned)jmp[6] << 8 |

		(unsigned)jmp[7];



	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",

	       (unsigned)(*ptr >> 32),

	       (unsigned)*ptr);



	/* 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(replaced, (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[0] = 0x48000008;	/* b +8 */



	if (probe_kernel_write((void *)ip, replaced, MCOUNT_INSN_SIZE))

		return -EPERM;



	return 0;

}



#else /* !PPC64 */

static int

__ftrace_make_nop(struct module *mod,

		  struct dyn_ftrace *rec, unsigned long addr)

{

	unsigned char replaced[MCOUNT_INSN_SIZE];

	unsigned int *op = (unsigned *)&replaced;

	unsigned char jmp[8];

	unsigned int *ptr = (unsigned int *)&jmp;

	unsigned long ip = rec->ip;

	unsigned long tramp;

	int offset;



	if (probe_kernel_read(replaced, (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:

	 * lis r11,sym@ha

	 * addi r11,r11,sym@l

	 * mtctr r11

	 * bctr

	 */



	DEBUGP("ip:%lx jumps to %lx", ip, tramp);



	/* Find where the trampoline jumps to */

	if (probe_kernel_read(jmp, (void *)tramp, 8)) {

		printk(KERN_ERR "Failed to read %lx\n", tramp);

		return -EFAULT;

	}



	DEBUGP(" %08x %08x ", ptr[0], ptr[1]);



	tramp = (ptr[1] & 0xffff) |

		((ptr[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[0] = PPC_NOP_INSTR;



	if (probe_kernel_write((void *)ip, replaced, MCOUNT_INSN_SIZE))

		return -EPERM;



	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 char replaced[MCOUNT_INSN_SIZE * 2];

	unsigned int *op = (unsigned *)&replaced;

	unsigned long ip = rec->ip;

	unsigned long offset;



	/* read where this goes */

	if (probe_kernel_read(replaced, (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;

	}



	/* now calculate a jump to the ftrace caller trampoline */

	offset = rec->arch.mod->arch.tramp - ip;



	if (test_offset(offset)) {

		printk(KERN_ERR "REL24 %li out of range!\n",

		       (long int)offset);

		return -EINVAL;

	}



	/* Set to "bl addr" */

	op[0] = branch_offset(offset);

	/* ld r2,40(r1) */

	op[1] = 0xe8410028;



	DEBUGP("write to %lx\n", rec->ip);



	if (probe_kernel_write((void *)ip, replaced, MCOUNT_INSN_SIZE * 2))

		return -EPERM;



	return 0;

}

#else

static int

__ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)

{

	unsigned char replaced[MCOUNT_INSN_SIZE];

	unsigned int *op = (unsigned *)&replaced;

	unsigned long ip = rec->ip;

	unsigned long offset;



	/* read where this goes */

	if (probe_kernel_read(replaced, (void *)ip, MCOUNT_INSN_SIZE))

		return -EFAULT;



	/* It should be pointing to a nop */

	if (op[0] != PPC_NOP_INSTR) {

		printk(KERN_ERR "Expected NOP but have %x\n", op[0]);

		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;

	}



	/* now calculate a jump to the ftrace caller trampoline */

	offset = rec->arch.mod->arch.tramp - ip;



	if (test_offset(offset)) {

		printk(KERN_ERR "REL24 %li out of range!\n",

		       (long int)offset);

		return -EINVAL;

	}



	/* Set to "bl addr" */

	op[0] = branch_offset(offset);



	DEBUGP("write to %lx\n", rec->ip);



	if (probe_kernel_write((void *)ip, replaced, MCOUNT_INSN_SIZE))

		return -EPERM;



	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 +521,10 @@ 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;

}

arch/powerpc/kernel/idle.c

+5 −0
Original line number Diff line number Diff line
@@ -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);

arch/powerpc/kernel/module_32.c

+10 −0
Original line number Diff line number Diff line
@@ -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;

}