diff options
Diffstat (limited to 'arch/sh/kernel/cpu/sh5')
| -rw-r--r-- | arch/sh/kernel/cpu/sh5/Makefile | 4 | ||||
| -rw-r--r-- | arch/sh/kernel/cpu/sh5/switchto.S | 198 | ||||
| -rw-r--r-- | arch/sh/kernel/cpu/sh5/unwind.c | 326 |
3 files changed, 527 insertions, 1 deletions
diff --git a/arch/sh/kernel/cpu/sh5/Makefile b/arch/sh/kernel/cpu/sh5/Makefile index 9778f9bdff3..7ea10732b5c 100644 --- a/arch/sh/kernel/cpu/sh5/Makefile +++ b/arch/sh/kernel/cpu/sh5/Makefile @@ -1 +1,3 @@ -obj-y := entry.o +obj-y := entry.o switchto.o + +obj-$(CONFIG_KALLSYMS) += unwind.o diff --git a/arch/sh/kernel/cpu/sh5/switchto.S b/arch/sh/kernel/cpu/sh5/switchto.S new file mode 100644 index 00000000000..45b2d90eed7 --- /dev/null +++ b/arch/sh/kernel/cpu/sh5/switchto.S @@ -0,0 +1,198 @@ +/* + * arch/sh64/kernel/switchto.S + * + * sh64 context switch + * + * Copyright (C) 2004 Richard Curnow + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. +*/ + + .section .text..SHmedia32,"ax" + .little + + .balign 32 + + .type sh64_switch_to,@function + .global sh64_switch_to + .global __sh64_switch_to_end +sh64_switch_to: + +/* Incoming args + r2 - prev + r3 - &prev->thread + r4 - next + r5 - &next->thread + + Outgoing results + r2 - last (=prev) : this just stays in r2 throughout + + Want to create a full (struct pt_regs) on the stack to allow backtracing + functions to work. However, we only need to populate the callee-save + register slots in this structure; since we're a function our ancestors must + have themselves preserved all caller saved state in the stack. This saves + some wasted effort since we won't need to look at the values. + + In particular, all caller-save registers are immediately available for + scratch use. + +*/ + +#define FRAME_SIZE (76*8 + 8) + + movi FRAME_SIZE, r0 + sub.l r15, r0, r15 + ! Do normal-style register save to support backtrace + + st.l r15, 0, r18 ! save link reg + st.l r15, 4, r14 ! save fp + add.l r15, r63, r14 ! setup frame pointer + + ! hopefully this looks normal to the backtrace now. + + addi.l r15, 8, r1 ! base of pt_regs + addi.l r1, 24, r0 ! base of pt_regs.regs + addi.l r0, (63*8), r8 ! base of pt_regs.trregs + + /* Note : to be fixed? + struct pt_regs is really designed for holding the state on entry + to an exception, i.e. pc,sr,regs etc. However, for the context + switch state, some of this is not required. But the unwinder takes + struct pt_regs * as an arg so we have to build this structure + to allow unwinding switched tasks in show_state() */ + + st.q r0, ( 9*8), r9 + st.q r0, (10*8), r10 + st.q r0, (11*8), r11 + st.q r0, (12*8), r12 + st.q r0, (13*8), r13 + st.q r0, (14*8), r14 ! for unwind, want to look as though we took a trap at + ! the point where the process is left in suspended animation, i.e. current + ! fp here, not the saved one. + st.q r0, (16*8), r16 + + st.q r0, (24*8), r24 + st.q r0, (25*8), r25 + st.q r0, (26*8), r26 + st.q r0, (27*8), r27 + st.q r0, (28*8), r28 + st.q r0, (29*8), r29 + st.q r0, (30*8), r30 + st.q r0, (31*8), r31 + st.q r0, (32*8), r32 + st.q r0, (33*8), r33 + st.q r0, (34*8), r34 + st.q r0, (35*8), r35 + + st.q r0, (44*8), r44 + st.q r0, (45*8), r45 + st.q r0, (46*8), r46 + st.q r0, (47*8), r47 + st.q r0, (48*8), r48 + st.q r0, (49*8), r49 + st.q r0, (50*8), r50 + st.q r0, (51*8), r51 + st.q r0, (52*8), r52 + st.q r0, (53*8), r53 + st.q r0, (54*8), r54 + st.q r0, (55*8), r55 + st.q r0, (56*8), r56 + st.q r0, (57*8), r57 + st.q r0, (58*8), r58 + st.q r0, (59*8), r59 + + ! do this early as pta->gettr has no pipeline forwarding (=> 5 cycle latency) + ! Use a local label to avoid creating a symbol that will confuse the ! + ! backtrace + pta .Lsave_pc, tr0 + + gettr tr5, r45 + gettr tr6, r46 + gettr tr7, r47 + st.q r8, (5*8), r45 + st.q r8, (6*8), r46 + st.q r8, (7*8), r47 + + ! Now switch context + gettr tr0, r9 + st.l r3, 0, r15 ! prev->thread.sp + st.l r3, 8, r1 ! prev->thread.kregs + st.l r3, 4, r9 ! prev->thread.pc + st.q r1, 0, r9 ! save prev->thread.pc into pt_regs->pc + + ! Load PC for next task (init value or save_pc later) + ld.l r5, 4, r18 ! next->thread.pc + ! Switch stacks + ld.l r5, 0, r15 ! next->thread.sp + ptabs r18, tr0 + + ! Update current + ld.l r4, 4, r9 ! next->thread_info (2nd element of next task_struct) + putcon r9, kcr0 ! current = next->thread_info + + ! go to save_pc for a reschedule, or the initial thread.pc for a new process + blink tr0, r63 + + ! Restore (when we come back to a previously saved task) +.Lsave_pc: + addi.l r15, 32, r0 ! r0 = next's regs + addi.l r0, (63*8), r8 ! r8 = next's tr_regs + + ld.q r8, (5*8), r45 + ld.q r8, (6*8), r46 + ld.q r8, (7*8), r47 + ptabs r45, tr5 + ptabs r46, tr6 + ptabs r47, tr7 + + ld.q r0, ( 9*8), r9 + ld.q r0, (10*8), r10 + ld.q r0, (11*8), r11 + ld.q r0, (12*8), r12 + ld.q r0, (13*8), r13 + ld.q r0, (14*8), r14 + ld.q r0, (16*8), r16 + + ld.q r0, (24*8), r24 + ld.q r0, (25*8), r25 + ld.q r0, (26*8), r26 + ld.q r0, (27*8), r27 + ld.q r0, (28*8), r28 + ld.q r0, (29*8), r29 + ld.q r0, (30*8), r30 + ld.q r0, (31*8), r31 + ld.q r0, (32*8), r32 + ld.q r0, (33*8), r33 + ld.q r0, (34*8), r34 + ld.q r0, (35*8), r35 + + ld.q r0, (44*8), r44 + ld.q r0, (45*8), r45 + ld.q r0, (46*8), r46 + ld.q r0, (47*8), r47 + ld.q r0, (48*8), r48 + ld.q r0, (49*8), r49 + ld.q r0, (50*8), r50 + ld.q r0, (51*8), r51 + ld.q r0, (52*8), r52 + ld.q r0, (53*8), r53 + ld.q r0, (54*8), r54 + ld.q r0, (55*8), r55 + ld.q r0, (56*8), r56 + ld.q r0, (57*8), r57 + ld.q r0, (58*8), r58 + ld.q r0, (59*8), r59 + + ! epilogue + ld.l r15, 0, r18 + ld.l r15, 4, r14 + ptabs r18, tr0 + movi FRAME_SIZE, r0 + add r15, r0, r15 + blink tr0, r63 +__sh64_switch_to_end: +.LFE1: + .size sh64_switch_to,.LFE1-sh64_switch_to + diff --git a/arch/sh/kernel/cpu/sh5/unwind.c b/arch/sh/kernel/cpu/sh5/unwind.c new file mode 100644 index 00000000000..1214c78e358 --- /dev/null +++ b/arch/sh/kernel/cpu/sh5/unwind.c @@ -0,0 +1,326 @@ +/* + * arch/sh64/kernel/unwind.c + * + * Copyright (C) 2004 Paul Mundt + * Copyright (C) 2004 Richard Curnow + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + */ +#include <linux/kallsyms.h> +#include <linux/kernel.h> +#include <linux/types.h> +#include <linux/errno.h> +#include <asm/page.h> +#include <asm/ptrace.h> +#include <asm/processor.h> +#include <asm/io.h> + +static u8 regcache[63]; + +/* + * Finding the previous stack frame isn't horribly straightforward as it is + * on some other platforms. In the sh64 case, we don't have "linked" stack + * frames, so we need to do a bit of work to determine the previous frame, + * and in turn, the previous r14/r18 pair. + * + * There are generally a few cases which determine where we can find out + * the r14/r18 values. In the general case, this can be determined by poking + * around the prologue of the symbol PC is in (note that we absolutely must + * have frame pointer support as well as the kernel symbol table mapped, + * otherwise we can't even get this far). + * + * In other cases, such as the interrupt/exception path, we can poke around + * the sp/fp. + * + * Notably, this entire approach is somewhat error prone, and in the event + * that the previous frame cannot be determined, that's all we can do. + * Either way, this still leaves us with a more correct backtrace then what + * we would be able to come up with by walking the stack (which is garbage + * for anything beyond the first frame). + * -- PFM. + */ +static int lookup_prev_stack_frame(unsigned long fp, unsigned long pc, + unsigned long *pprev_fp, unsigned long *pprev_pc, + struct pt_regs *regs) +{ + const char *sym; + char namebuf[128]; + unsigned long offset; + unsigned long prologue = 0; + unsigned long fp_displacement = 0; + unsigned long fp_prev = 0; + unsigned long offset_r14 = 0, offset_r18 = 0; + int i, found_prologue_end = 0; + + sym = kallsyms_lookup(pc, NULL, &offset, NULL, namebuf); + if (!sym) + return -EINVAL; + + prologue = pc - offset; + if (!prologue) + return -EINVAL; + + /* Validate fp, to avoid risk of dereferencing a bad pointer later. + Assume 128Mb since that's the amount of RAM on a Cayman. Modify + when there is an SH-5 board with more. */ + if ((fp < (unsigned long) phys_to_virt(__MEMORY_START)) || + (fp >= (unsigned long)(phys_to_virt(__MEMORY_START)) + 128*1024*1024) || + ((fp & 7) != 0)) { + return -EINVAL; + } + + /* + * Depth to walk, depth is completely arbitrary. + */ + for (i = 0; i < 100; i++, prologue += sizeof(unsigned long)) { + unsigned long op; + u8 major, minor; + u8 src, dest, disp; + + op = *(unsigned long *)prologue; + + major = (op >> 26) & 0x3f; + src = (op >> 20) & 0x3f; + minor = (op >> 16) & 0xf; + disp = (op >> 10) & 0x3f; + dest = (op >> 4) & 0x3f; + + /* + * Stack frame creation happens in a number of ways.. in the + * general case when the stack frame is less than 511 bytes, + * it's generally created by an addi or addi.l: + * + * addi/addi.l r15, -FRAME_SIZE, r15 + * + * in the event that the frame size is bigger than this, it's + * typically created using a movi/sub pair as follows: + * + * movi FRAME_SIZE, rX + * sub r15, rX, r15 + */ + + switch (major) { + case (0x00 >> 2): + switch (minor) { + case 0x8: /* add.l */ + case 0x9: /* add */ + /* Look for r15, r63, r14 */ + if (src == 15 && disp == 63 && dest == 14) + found_prologue_end = 1; + + break; + case 0xa: /* sub.l */ + case 0xb: /* sub */ + if (src != 15 || dest != 15) + continue; + + fp_displacement -= regcache[disp]; + fp_prev = fp - fp_displacement; + break; + } + break; + case (0xa8 >> 2): /* st.l */ + if (src != 15) + continue; + + switch (dest) { + case 14: + if (offset_r14 || fp_displacement == 0) + continue; + + offset_r14 = (u64)(((((s64)op >> 10) & 0x3ff) << 54) >> 54); + offset_r14 *= sizeof(unsigned long); + offset_r14 += fp_displacement; + break; + case 18: + if (offset_r18 || fp_displacement == 0) + continue; + + offset_r18 = (u64)(((((s64)op >> 10) & 0x3ff) << 54) >> 54); + offset_r18 *= sizeof(unsigned long); + offset_r18 += fp_displacement; + break; + } + + break; + case (0xcc >> 2): /* movi */ + if (dest >= 63) { + printk(KERN_NOTICE "%s: Invalid dest reg %d " + "specified in movi handler. Failed " + "opcode was 0x%lx: ", __FUNCTION__, + dest, op); + + continue; + } + + /* Sign extend */ + regcache[dest] = + ((((s64)(u64)op >> 10) & 0xffff) << 54) >> 54; + break; + case (0xd0 >> 2): /* addi */ + case (0xd4 >> 2): /* addi.l */ + /* Look for r15, -FRAME_SIZE, r15 */ + if (src != 15 || dest != 15) + continue; + + /* Sign extended frame size.. */ + fp_displacement += + (u64)(((((s64)op >> 10) & 0x3ff) << 54) >> 54); + fp_prev = fp - fp_displacement; + break; + } + + if (found_prologue_end && offset_r14 && (offset_r18 || *pprev_pc) && fp_prev) + break; + } + + if (offset_r14 == 0 || fp_prev == 0) { + if (!offset_r14) + pr_debug("Unable to find r14 offset\n"); + if (!fp_prev) + pr_debug("Unable to find previous fp\n"); + + return -EINVAL; + } + + /* For innermost leaf function, there might not be a offset_r18 */ + if (!*pprev_pc && (offset_r18 == 0)) + return -EINVAL; + + *pprev_fp = *(unsigned long *)(fp_prev + offset_r14); + + if (offset_r18) + *pprev_pc = *(unsigned long *)(fp_prev + offset_r18); + + *pprev_pc &= ~1; + + return 0; +} + +/* Don't put this on the stack since we'll want to call sh64_unwind + * when we're close to underflowing the stack anyway. */ +static struct pt_regs here_regs; + +extern const char syscall_ret; +extern const char ret_from_syscall; +extern const char ret_from_exception; +extern const char ret_from_irq; + +static void sh64_unwind_inner(struct pt_regs *regs); + +static void unwind_nested (unsigned long pc, unsigned long fp) +{ + if ((fp >= __MEMORY_START) && + ((fp & 7) == 0)) { + sh64_unwind_inner((struct pt_regs *) fp); + } +} + +static void sh64_unwind_inner(struct pt_regs *regs) +{ + unsigned long pc, fp; + int ofs = 0; + int first_pass; + + pc = regs->pc & ~1; + fp = regs->regs[14]; + + first_pass = 1; + for (;;) { + int cond; + unsigned long next_fp, next_pc; + + if (pc == ((unsigned long) &syscall_ret & ~1)) { + printk("SYSCALL\n"); + unwind_nested(pc,fp); + return; + } + + if (pc == ((unsigned long) &ret_from_syscall & ~1)) { + printk("SYSCALL (PREEMPTED)\n"); + unwind_nested(pc,fp); + return; + } + + /* In this case, the PC is discovered by lookup_prev_stack_frame but + it has 4 taken off it to look like the 'caller' */ + if (pc == ((unsigned long) &ret_from_exception & ~1)) { + printk("EXCEPTION\n"); + unwind_nested(pc,fp); + return; + } + + if (pc == ((unsigned long) &ret_from_irq & ~1)) { + printk("IRQ\n"); + unwind_nested(pc,fp); + return; + } + + cond = ((pc >= __MEMORY_START) && (fp >= __MEMORY_START) && + ((pc & 3) == 0) && ((fp & 7) == 0)); + + pc -= ofs; + + printk("[<%08lx>] ", pc); + print_symbol("%s\n", pc); + + if (first_pass) { + /* If the innermost frame is a leaf function, it's + * possible that r18 is never saved out to the stack. + */ + next_pc = regs->regs[18]; + } else { + next_pc = 0; + } + + if (lookup_prev_stack_frame(fp, pc, &next_fp, &next_pc, regs) == 0) { + ofs = sizeof(unsigned long); + pc = next_pc & ~1; + fp = next_fp; + } else { + printk("Unable to lookup previous stack frame\n"); + break; + } + first_pass = 0; + } + + printk("\n"); + +} + +void sh64_unwind(struct pt_regs *regs) +{ + if (!regs) { + /* + * Fetch current regs if we have no other saved state to back + * trace from. + */ + regs = &here_regs; + + __asm__ __volatile__ ("ori r14, 0, %0" : "=r" (regs->regs[14])); + __asm__ __volatile__ ("ori r15, 0, %0" : "=r" (regs->regs[15])); + __asm__ __volatile__ ("ori r18, 0, %0" : "=r" (regs->regs[18])); + + __asm__ __volatile__ ("gettr tr0, %0" : "=r" (regs->tregs[0])); + __asm__ __volatile__ ("gettr tr1, %0" : "=r" (regs->tregs[1])); + __asm__ __volatile__ ("gettr tr2, %0" : "=r" (regs->tregs[2])); + __asm__ __volatile__ ("gettr tr3, %0" : "=r" (regs->tregs[3])); + __asm__ __volatile__ ("gettr tr4, %0" : "=r" (regs->tregs[4])); + __asm__ __volatile__ ("gettr tr5, %0" : "=r" (regs->tregs[5])); + __asm__ __volatile__ ("gettr tr6, %0" : "=r" (regs->tregs[6])); + __asm__ __volatile__ ("gettr tr7, %0" : "=r" (regs->tregs[7])); + + __asm__ __volatile__ ( + "pta 0f, tr0\n\t" + "blink tr0, %0\n\t" + "0: nop" + : "=r" (regs->pc) + ); + } + + printk("\nCall Trace:\n"); + sh64_unwind_inner(regs); +} + |