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-rw-r--r--arch/arm/kernel/entry-common.S124
-rw-r--r--arch/arm/kernel/etm.c4
-rw-r--r--arch/arm/kernel/module.c34
3 files changed, 117 insertions, 45 deletions
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index 2c1db77d7848..f05a35a59694 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -92,75 +92,111 @@ ENDPROC(ret_from_fork)
#define CALL(x) .long x
#ifdef CONFIG_FUNCTION_TRACER
+/*
+ * When compiling with -pg, gcc inserts a call to the mcount routine at the
+ * start of every function. In mcount, apart from the function's address (in
+ * lr), we need to get hold of the function's caller's address.
+ *
+ * Older GCCs (pre-4.4) inserted a call to a routine called mcount like this:
+ *
+ * bl mcount
+ *
+ * These versions have the limitation that in order for the mcount routine to
+ * be able to determine the function's caller's address, an APCS-style frame
+ * pointer (which is set up with something like the code below) is required.
+ *
+ * mov ip, sp
+ * push {fp, ip, lr, pc}
+ * sub fp, ip, #4
+ *
+ * With EABI, these frame pointers are not available unless -mapcs-frame is
+ * specified, and if building as Thumb-2, not even then.
+ *
+ * Newer GCCs (4.4+) solve this problem by introducing a new version of mcount,
+ * with call sites like:
+ *
+ * push {lr}
+ * bl __gnu_mcount_nc
+ *
+ * With these compilers, frame pointers are not necessary.
+ *
+ * mcount can be thought of as a function called in the middle of a subroutine
+ * call. As such, it needs to be transparent for both the caller and the
+ * callee: the original lr needs to be restored when leaving mcount, and no
+ * registers should be clobbered. (In the __gnu_mcount_nc implementation, we
+ * clobber the ip register. This is OK because the ARM calling convention
+ * allows it to be clobbered in subroutines and doesn't use it to hold
+ * parameters.)
+ */
#ifdef CONFIG_DYNAMIC_FTRACE
ENTRY(mcount)
- stmdb sp!, {r0-r3, lr}
- mov r0, lr
- sub r0, r0, #MCOUNT_INSN_SIZE
+ stmdb sp!, {r0-r3, lr}
+ mov r0, lr
+ sub r0, r0, #MCOUNT_INSN_SIZE
.globl mcount_call
mcount_call:
- bl ftrace_stub
- ldr lr, [fp, #-4] @ restore lr
- ldmia sp!, {r0-r3, pc}
+ bl ftrace_stub
+ ldr lr, [fp, #-4] @ restore lr
+ ldmia sp!, {r0-r3, pc}
ENTRY(ftrace_caller)
- stmdb sp!, {r0-r3, lr}
- ldr r1, [fp, #-4]
- mov r0, lr
- sub r0, r0, #MCOUNT_INSN_SIZE
+ stmdb sp!, {r0-r3, lr}
+ ldr r1, [fp, #-4]
+ mov r0, lr
+ sub r0, r0, #MCOUNT_INSN_SIZE
.globl ftrace_call
ftrace_call:
- bl ftrace_stub
- ldr lr, [fp, #-4] @ restore lr
- ldmia sp!, {r0-r3, pc}
+ bl ftrace_stub
+ ldr lr, [fp, #-4] @ restore lr
+ ldmia sp!, {r0-r3, pc}
#else
ENTRY(__gnu_mcount_nc)
- stmdb sp!, {r0-r3, lr}
- ldr r0, =ftrace_trace_function
- ldr r2, [r0]
- adr r0, ftrace_stub
- cmp r0, r2
- bne gnu_trace
- ldmia sp!, {r0-r3, ip, lr}
- mov pc, ip
+ stmdb sp!, {r0-r3, lr}
+ ldr r0, =ftrace_trace_function
+ ldr r2, [r0]
+ adr r0, ftrace_stub
+ cmp r0, r2
+ bne gnu_trace
+ ldmia sp!, {r0-r3, ip, lr}
+ mov pc, ip
gnu_trace:
- ldr r1, [sp, #20] @ lr of instrumented routine
- mov r0, lr
- sub r0, r0, #MCOUNT_INSN_SIZE
- mov lr, pc
- mov pc, r2
- ldmia sp!, {r0-r3, ip, lr}
- mov pc, ip
+ ldr r1, [sp, #20] @ lr of instrumented routine
+ mov r0, lr
+ sub r0, r0, #MCOUNT_INSN_SIZE
+ mov lr, pc
+ mov pc, r2
+ ldmia sp!, {r0-r3, ip, lr}
+ mov pc, ip
ENTRY(mcount)
- stmdb sp!, {r0-r3, lr}
- ldr r0, =ftrace_trace_function
- ldr r2, [r0]
- adr r0, ftrace_stub
- cmp r0, r2
- bne trace
- ldr lr, [fp, #-4] @ restore lr
- ldmia sp!, {r0-r3, pc}
+ stmdb sp!, {r0-r3, lr}
+ ldr r0, =ftrace_trace_function
+ ldr r2, [r0]
+ adr r0, ftrace_stub
+ cmp r0, r2
+ bne trace
+ ldr lr, [fp, #-4] @ restore lr
+ ldmia sp!, {r0-r3, pc}
trace:
- ldr r1, [fp, #-4] @ lr of instrumented routine
- mov r0, lr
- sub r0, r0, #MCOUNT_INSN_SIZE
- mov lr, pc
- mov pc, r2
- ldr lr, [fp, #-4] @ restore lr
- ldmia sp!, {r0-r3, pc}
+ ldr r1, [fp, #-4] @ lr of instrumented routine
+ mov r0, lr
+ sub r0, r0, #MCOUNT_INSN_SIZE
+ mov lr, pc
+ mov pc, r2
+ ldr lr, [fp, #-4] @ restore lr
+ ldmia sp!, {r0-r3, pc}
#endif /* CONFIG_DYNAMIC_FTRACE */
.globl ftrace_stub
ftrace_stub:
- mov pc, lr
+ mov pc, lr
#endif /* CONFIG_FUNCTION_TRACER */
diff --git a/arch/arm/kernel/etm.c b/arch/arm/kernel/etm.c
index 827753966301..56418f98cd01 100644
--- a/arch/arm/kernel/etm.c
+++ b/arch/arm/kernel/etm.c
@@ -543,7 +543,9 @@ static int __init etm_probe(struct amba_device *dev, struct amba_id *id)
t->etm_portsz = 1;
etm_unlock(t);
- ret = etm_readl(t, CSCR_PRSR);
+ (void)etm_readl(t, ETMMR_PDSR);
+ /* dummy first read */
+ (void)etm_readl(&tracer, ETMMR_OSSRR);
t->ncmppairs = etm_readl(t, ETMR_CONFCODE) & 0xf;
etm_writel(t, 0x440, ETMR_CTRL);
diff --git a/arch/arm/kernel/module.c b/arch/arm/kernel/module.c
index c628bdf6c430..6b4605893f1e 100644
--- a/arch/arm/kernel/module.c
+++ b/arch/arm/kernel/module.c
@@ -102,7 +102,9 @@ apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex,
unsigned long loc;
Elf32_Sym *sym;
s32 offset;
+#ifdef CONFIG_THUMB2_KERNEL
u32 upper, lower, sign, j1, j2;
+#endif
offset = ELF32_R_SYM(rel->r_info);
if (offset < 0 || offset > (symsec->sh_size / sizeof(Elf32_Sym))) {
@@ -185,6 +187,7 @@ apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex,
(offset & 0x0fff);
break;
+#ifdef CONFIG_THUMB2_KERNEL
case R_ARM_THM_CALL:
case R_ARM_THM_JUMP24:
upper = *(u16 *)loc;
@@ -233,9 +236,40 @@ apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex,
*(u16 *)(loc + 2) = (u16)((lower & 0xd000) |
(j1 << 13) | (j2 << 11) |
((offset >> 1) & 0x07ff));
+ break;
+
+ case R_ARM_THM_MOVW_ABS_NC:
+ case R_ARM_THM_MOVT_ABS:
upper = *(u16 *)loc;
lower = *(u16 *)(loc + 2);
+
+ /*
+ * MOVT/MOVW instructions encoding in Thumb-2:
+ *
+ * i = upper[10]
+ * imm4 = upper[3:0]
+ * imm3 = lower[14:12]
+ * imm8 = lower[7:0]
+ *
+ * imm16 = imm4:i:imm3:imm8
+ */
+ offset = ((upper & 0x000f) << 12) |
+ ((upper & 0x0400) << 1) |
+ ((lower & 0x7000) >> 4) | (lower & 0x00ff);
+ offset = (offset ^ 0x8000) - 0x8000;
+ offset += sym->st_value;
+
+ if (ELF32_R_TYPE(rel->r_info) == R_ARM_THM_MOVT_ABS)
+ offset >>= 16;
+
+ *(u16 *)loc = (u16)((upper & 0xfbf0) |
+ ((offset & 0xf000) >> 12) |
+ ((offset & 0x0800) >> 1));
+ *(u16 *)(loc + 2) = (u16)((lower & 0x8f00) |
+ ((offset & 0x0700) << 4) |
+ (offset & 0x00ff));
break;
+#endif
default:
printk(KERN_ERR "%s: unknown relocation: %u\n",
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-21 18:14:56 +0100