linux/arch/riscv/kernel/ptrace.c
Andy Chiu 9300f00439
RISC-V: Add ptrace support for vectors
This patch add back the ptrace support with the following fix:
 - Define NT_RISCV_CSR and re-number NT_RISCV_VECTOR to prevent
   conflicting with gdb's NT_RISCV_CSR.
 - Use struct __riscv_v_regset_state to handle ptrace requests

Since gdb does not directly include the note description header in
Linux and has already defined NT_RISCV_CSR as 0x900, we decide to
sync with gdb and renumber NT_RISCV_VECTOR to solve and prevent future
conflicts.

Fixes: 0c59922c76 ("riscv: Add ptrace vector support")
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Link: https://lore.kernel.org/r/20230825050248.32681-1-andy.chiu@sifive.com
[Palmer: Drop the unused "size" variable in riscv_vr_set().]
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-09-01 13:05:38 -07:00

388 lines
9.5 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright 2010 Tilera Corporation. All Rights Reserved.
* Copyright 2015 Regents of the University of California
* Copyright 2017 SiFive
*
* Copied from arch/tile/kernel/ptrace.c
*/
#include <asm/vector.h>
#include <asm/ptrace.h>
#include <asm/syscall.h>
#include <asm/thread_info.h>
#include <asm/switch_to.h>
#include <linux/audit.h>
#include <linux/compat.h>
#include <linux/ptrace.h>
#include <linux/elf.h>
#include <linux/regset.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
enum riscv_regset {
REGSET_X,
#ifdef CONFIG_FPU
REGSET_F,
#endif
#ifdef CONFIG_RISCV_ISA_V
REGSET_V,
#endif
};
static int riscv_gpr_get(struct task_struct *target,
const struct user_regset *regset,
struct membuf to)
{
return membuf_write(&to, task_pt_regs(target),
sizeof(struct user_regs_struct));
}
static int riscv_gpr_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
struct pt_regs *regs;
regs = task_pt_regs(target);
return user_regset_copyin(&pos, &count, &kbuf, &ubuf, regs, 0, -1);
}
#ifdef CONFIG_FPU
static int riscv_fpr_get(struct task_struct *target,
const struct user_regset *regset,
struct membuf to)
{
struct __riscv_d_ext_state *fstate = &target->thread.fstate;
if (target == current)
fstate_save(current, task_pt_regs(current));
membuf_write(&to, fstate, offsetof(struct __riscv_d_ext_state, fcsr));
membuf_store(&to, fstate->fcsr);
return membuf_zero(&to, 4); // explicitly pad
}
static int riscv_fpr_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
int ret;
struct __riscv_d_ext_state *fstate = &target->thread.fstate;
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, fstate, 0,
offsetof(struct __riscv_d_ext_state, fcsr));
if (!ret) {
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, fstate, 0,
offsetof(struct __riscv_d_ext_state, fcsr) +
sizeof(fstate->fcsr));
}
return ret;
}
#endif
#ifdef CONFIG_RISCV_ISA_V
static int riscv_vr_get(struct task_struct *target,
const struct user_regset *regset,
struct membuf to)
{
struct __riscv_v_ext_state *vstate = &target->thread.vstate;
struct __riscv_v_regset_state ptrace_vstate;
if (!riscv_v_vstate_query(task_pt_regs(target)))
return -EINVAL;
/*
* Ensure the vector registers have been saved to the memory before
* copying them to membuf.
*/
if (target == current)
riscv_v_vstate_save(current, task_pt_regs(current));
ptrace_vstate.vstart = vstate->vstart;
ptrace_vstate.vl = vstate->vl;
ptrace_vstate.vtype = vstate->vtype;
ptrace_vstate.vcsr = vstate->vcsr;
ptrace_vstate.vlenb = vstate->vlenb;
/* Copy vector header from vstate. */
membuf_write(&to, &ptrace_vstate, sizeof(struct __riscv_v_regset_state));
/* Copy all the vector registers from vstate. */
return membuf_write(&to, vstate->datap, riscv_v_vsize);
}
static int riscv_vr_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
int ret;
struct __riscv_v_ext_state *vstate = &target->thread.vstate;
struct __riscv_v_regset_state ptrace_vstate;
if (!riscv_v_vstate_query(task_pt_regs(target)))
return -EINVAL;
/* Copy rest of the vstate except datap */
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &ptrace_vstate, 0,
sizeof(struct __riscv_v_regset_state));
if (unlikely(ret))
return ret;
if (vstate->vlenb != ptrace_vstate.vlenb)
return -EINVAL;
vstate->vstart = ptrace_vstate.vstart;
vstate->vl = ptrace_vstate.vl;
vstate->vtype = ptrace_vstate.vtype;
vstate->vcsr = ptrace_vstate.vcsr;
/* Copy all the vector registers. */
pos = 0;
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, vstate->datap,
0, riscv_v_vsize);
return ret;
}
#endif
static const struct user_regset riscv_user_regset[] = {
[REGSET_X] = {
.core_note_type = NT_PRSTATUS,
.n = ELF_NGREG,
.size = sizeof(elf_greg_t),
.align = sizeof(elf_greg_t),
.regset_get = riscv_gpr_get,
.set = riscv_gpr_set,
},
#ifdef CONFIG_FPU
[REGSET_F] = {
.core_note_type = NT_PRFPREG,
.n = ELF_NFPREG,
.size = sizeof(elf_fpreg_t),
.align = sizeof(elf_fpreg_t),
.regset_get = riscv_fpr_get,
.set = riscv_fpr_set,
},
#endif
#ifdef CONFIG_RISCV_ISA_V
[REGSET_V] = {
.core_note_type = NT_RISCV_VECTOR,
.align = 16,
.n = ((32 * RISCV_MAX_VLENB) +
sizeof(struct __riscv_v_regset_state)) / sizeof(__u32),
.size = sizeof(__u32),
.regset_get = riscv_vr_get,
.set = riscv_vr_set,
},
#endif
};
static const struct user_regset_view riscv_user_native_view = {
.name = "riscv",
.e_machine = EM_RISCV,
.regsets = riscv_user_regset,
.n = ARRAY_SIZE(riscv_user_regset),
};
struct pt_regs_offset {
const char *name;
int offset;
};
#define REG_OFFSET_NAME(r) {.name = #r, .offset = offsetof(struct pt_regs, r)}
#define REG_OFFSET_END {.name = NULL, .offset = 0}
static const struct pt_regs_offset regoffset_table[] = {
REG_OFFSET_NAME(epc),
REG_OFFSET_NAME(ra),
REG_OFFSET_NAME(sp),
REG_OFFSET_NAME(gp),
REG_OFFSET_NAME(tp),
REG_OFFSET_NAME(t0),
REG_OFFSET_NAME(t1),
REG_OFFSET_NAME(t2),
REG_OFFSET_NAME(s0),
REG_OFFSET_NAME(s1),
REG_OFFSET_NAME(a0),
REG_OFFSET_NAME(a1),
REG_OFFSET_NAME(a2),
REG_OFFSET_NAME(a3),
REG_OFFSET_NAME(a4),
REG_OFFSET_NAME(a5),
REG_OFFSET_NAME(a6),
REG_OFFSET_NAME(a7),
REG_OFFSET_NAME(s2),
REG_OFFSET_NAME(s3),
REG_OFFSET_NAME(s4),
REG_OFFSET_NAME(s5),
REG_OFFSET_NAME(s6),
REG_OFFSET_NAME(s7),
REG_OFFSET_NAME(s8),
REG_OFFSET_NAME(s9),
REG_OFFSET_NAME(s10),
REG_OFFSET_NAME(s11),
REG_OFFSET_NAME(t3),
REG_OFFSET_NAME(t4),
REG_OFFSET_NAME(t5),
REG_OFFSET_NAME(t6),
REG_OFFSET_NAME(status),
REG_OFFSET_NAME(badaddr),
REG_OFFSET_NAME(cause),
REG_OFFSET_NAME(orig_a0),
REG_OFFSET_END,
};
/**
* regs_query_register_offset() - query register offset from its name
* @name: the name of a register
*
* regs_query_register_offset() returns the offset of a register in struct
* pt_regs from its name. If the name is invalid, this returns -EINVAL;
*/
int regs_query_register_offset(const char *name)
{
const struct pt_regs_offset *roff;
for (roff = regoffset_table; roff->name != NULL; roff++)
if (!strcmp(roff->name, name))
return roff->offset;
return -EINVAL;
}
/**
* regs_within_kernel_stack() - check the address in the stack
* @regs: pt_regs which contains kernel stack pointer.
* @addr: address which is checked.
*
* regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
* If @addr is within the kernel stack, it returns true. If not, returns false.
*/
static bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
{
return (addr & ~(THREAD_SIZE - 1)) ==
(kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1));
}
/**
* regs_get_kernel_stack_nth() - get Nth entry of the stack
* @regs: pt_regs which contains kernel stack pointer.
* @n: stack entry number.
*
* regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
* is specified by @regs. If the @n th entry is NOT in the kernel stack,
* this returns 0.
*/
unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
{
unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
addr += n;
if (regs_within_kernel_stack(regs, (unsigned long)addr))
return *addr;
else
return 0;
}
void ptrace_disable(struct task_struct *child)
{
}
long arch_ptrace(struct task_struct *child, long request,
unsigned long addr, unsigned long data)
{
long ret = -EIO;
switch (request) {
default:
ret = ptrace_request(child, request, addr, data);
break;
}
return ret;
}
#ifdef CONFIG_COMPAT
static int compat_riscv_gpr_get(struct task_struct *target,
const struct user_regset *regset,
struct membuf to)
{
struct compat_user_regs_struct cregs;
regs_to_cregs(&cregs, task_pt_regs(target));
return membuf_write(&to, &cregs,
sizeof(struct compat_user_regs_struct));
}
static int compat_riscv_gpr_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
int ret;
struct compat_user_regs_struct cregs;
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &cregs, 0, -1);
cregs_to_regs(&cregs, task_pt_regs(target));
return ret;
}
static const struct user_regset compat_riscv_user_regset[] = {
[REGSET_X] = {
.core_note_type = NT_PRSTATUS,
.n = ELF_NGREG,
.size = sizeof(compat_elf_greg_t),
.align = sizeof(compat_elf_greg_t),
.regset_get = compat_riscv_gpr_get,
.set = compat_riscv_gpr_set,
},
#ifdef CONFIG_FPU
[REGSET_F] = {
.core_note_type = NT_PRFPREG,
.n = ELF_NFPREG,
.size = sizeof(elf_fpreg_t),
.align = sizeof(elf_fpreg_t),
.regset_get = riscv_fpr_get,
.set = riscv_fpr_set,
},
#endif
};
static const struct user_regset_view compat_riscv_user_native_view = {
.name = "riscv",
.e_machine = EM_RISCV,
.regsets = compat_riscv_user_regset,
.n = ARRAY_SIZE(compat_riscv_user_regset),
};
long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
compat_ulong_t caddr, compat_ulong_t cdata)
{
long ret = -EIO;
switch (request) {
default:
ret = compat_ptrace_request(child, request, caddr, cdata);
break;
}
return ret;
}
#endif /* CONFIG_COMPAT */
const struct user_regset_view *task_user_regset_view(struct task_struct *task)
{
#ifdef CONFIG_COMPAT
if (test_tsk_thread_flag(task, TIF_32BIT))
return &compat_riscv_user_native_view;
else
#endif
return &riscv_user_native_view;
}