Luis Machado via Gdb-patches <gdb-patches@sourceware.org> writes:
> This is a patch in preparation to upcoming patches enabling SME support. It
> attempts to simplify the gdb/gdbserver shared interface used to read/write
> SVE registers.
>
> Where the current code makes use of unique_ptr, allocating a new buffer by
> hand and passing a buffer around, this patch makes that code use
> gdb::byte_vector and passes a reference to this byte vector to the functions,
> allowing the functions to have ready access to the size of the buffer.
Nice!
> It also shares a bit more code between gdb and gdbserver, in particular around
> handling of ptrace get/set requests for SVE.
Also nice!
> diff --git a/gdb/nat/aarch64-scalable-linux-ptrace.c b/gdb/nat/aarch64-scalable-linux-ptrace.c
> index cc43f510892..192eebcda19 100644
> --- a/gdb/nat/aarch64-scalable-linux-ptrace.c
> +++ b/gdb/nat/aarch64-scalable-linux-ptrace.c
> @@ -120,28 +120,44 @@ aarch64_sve_set_vq (int tid, struct reg_buffer_common *reg_buf)
>
> /* See nat/aarch64-scalable-linux-ptrace.h. */
>
> -std::unique_ptr<gdb_byte[]>
> -aarch64_sve_get_sveregs (int tid)
> +gdb::byte_vector
> +aarch64_fetch_sve_regset (int tid)
> {
> - struct iovec iovec;
> uint64_t vq = aarch64_sve_get_vq (tid);
>
> if (vq == 0)
> - perror_with_name (_("Unable to fetch SVE register header"));
> + perror_with_name (_("Unable to fetch SVE vector length"));
>
> /* A ptrace call with NT_ARM_SVE will return a header followed by either a
> dump of all the SVE and FP registers, or an fpsimd structure (identical to
> the one returned by NT_FPREGSET) if the kernel has not yet executed any
> SVE code. Make sure we allocate enough space for a full SVE dump. */
>
> - iovec.iov_len = SVE_PT_SIZE (vq, SVE_PT_REGS_SVE);
> - std::unique_ptr<gdb_byte[]> buf (new gdb_byte[iovec.iov_len]);
> - iovec.iov_base = buf.get ();
> + gdb::byte_vector sve_state (SVE_PT_SIZE (vq, SVE_PT_REGS_SVE), 0);
> +
> + struct iovec iovec;
> + iovec.iov_base = sve_state.data ();
> + iovec.iov_len = sve_state.size ();
>
> if (ptrace (PTRACE_GETREGSET, tid, NT_ARM_SVE, &iovec) < 0)
> perror_with_name (_("Unable to fetch SVE registers"));
>
> - return buf;
> + return sve_state;
> +}
> +
> +/* See nat/aarch64-scalable-linux-ptrace.h. */
> +
> +bool
This function always returns true, and its only caller doesn't use the
return value. Should it return void instead?
> +aarch64_store_sve_regset (int tid, const gdb::byte_vector &sve_state)
> +{
> + struct iovec iovec;
> + iovec.iov_base = (void *) sve_state.data ();
Minor nit: is the cast necessary? The code looks cleaner without it.
Also, it's not used in aarch64_fetch_sve_regset.
> + else
> + {
> + /* Otherwise, reformat the fpsimd structure into a full SVE set, by
> + expanding the V registers (working backwards so we don't splat
> + registers before they are copied) and using zero for everything
> + else.
> + Note that enough space for a full SVE dump was originally allocated
> + for base. */
> +
> + header->flags |= SVE_PT_REGS_SVE;
> + header->size = SVE_PT_SIZE (vq, SVE_PT_REGS_SVE);
> +
> + memcpy (base + SVE_PT_SVE_FPSR_OFFSET (vq), &fpsimd->fpsr,
> + sizeof (uint32_t));
> + memcpy (base + SVE_PT_SVE_FPCR_OFFSET (vq), &fpsimd->fpcr,
> + sizeof (uint32_t));
> +
> + for (int i = AARCH64_SVE_Z_REGS_NUM; i >= 0 ; i--)
Shouldn't i start from AARCH64_SVE_Z_REGS_NUM - 1? If this is correct, a
comment explaining why would be helpful.
On 7/24/23 17:19, Thiago Jung Bauermann wrote:
>
> Luis Machado via Gdb-patches <gdb-patches@sourceware.org> writes:
>
>> This is a patch in preparation to upcoming patches enabling SME support. It
>> attempts to simplify the gdb/gdbserver shared interface used to read/write
>> SVE registers.
>>
>> Where the current code makes use of unique_ptr, allocating a new buffer by
>> hand and passing a buffer around, this patch makes that code use
>> gdb::byte_vector and passes a reference to this byte vector to the functions,
>> allowing the functions to have ready access to the size of the buffer.
>
> Nice!
>
>> It also shares a bit more code between gdb and gdbserver, in particular around
>> handling of ptrace get/set requests for SVE.
>
> Also nice!
>
>> diff --git a/gdb/nat/aarch64-scalable-linux-ptrace.c b/gdb/nat/aarch64-scalable-linux-ptrace.c
>> index cc43f510892..192eebcda19 100644
>> --- a/gdb/nat/aarch64-scalable-linux-ptrace.c
>> +++ b/gdb/nat/aarch64-scalable-linux-ptrace.c
>> @@ -120,28 +120,44 @@ aarch64_sve_set_vq (int tid, struct reg_buffer_common *reg_buf)
>>
>> /* See nat/aarch64-scalable-linux-ptrace.h. */
>>
>> -std::unique_ptr<gdb_byte[]>
>> -aarch64_sve_get_sveregs (int tid)
>> +gdb::byte_vector
>> +aarch64_fetch_sve_regset (int tid)
>> {
>> - struct iovec iovec;
>> uint64_t vq = aarch64_sve_get_vq (tid);
>>
>> if (vq == 0)
>> - perror_with_name (_("Unable to fetch SVE register header"));
>> + perror_with_name (_("Unable to fetch SVE vector length"));
>>
>> /* A ptrace call with NT_ARM_SVE will return a header followed by either a
>> dump of all the SVE and FP registers, or an fpsimd structure (identical to
>> the one returned by NT_FPREGSET) if the kernel has not yet executed any
>> SVE code. Make sure we allocate enough space for a full SVE dump. */
>>
>> - iovec.iov_len = SVE_PT_SIZE (vq, SVE_PT_REGS_SVE);
>> - std::unique_ptr<gdb_byte[]> buf (new gdb_byte[iovec.iov_len]);
>> - iovec.iov_base = buf.get ();
>> + gdb::byte_vector sve_state (SVE_PT_SIZE (vq, SVE_PT_REGS_SVE), 0);
>> +
>> + struct iovec iovec;
>> + iovec.iov_base = sve_state.data ();
>> + iovec.iov_len = sve_state.size ();
>>
>> if (ptrace (PTRACE_GETREGSET, tid, NT_ARM_SVE, &iovec) < 0)
>> perror_with_name (_("Unable to fetch SVE registers"));
>>
>> - return buf;
>> + return sve_state;
>> +}
>> +
>> +/* See nat/aarch64-scalable-linux-ptrace.h. */
>> +
>> +bool
>
> This function always returns true, and its only caller doesn't use the
> return value. Should it return void instead?
>
I think it is reasonable for now. An earlier iteration of this patch used to let an error be handled by the callers, and I changed that.
I'll get it updated, and also change the same for the za regset.
>> +aarch64_store_sve_regset (int tid, const gdb::byte_vector &sve_state)
>> +{
>> + struct iovec iovec;
>> + iovec.iov_base = (void *) sve_state.data ();
>
> Minor nit: is the cast necessary? The code looks cleaner without it.
> Also, it's not used in aarch64_fetch_sve_regset.
>
I don't think it is needed. Probably an artifact of when the code used unique_ptr's.
>> + else
>> + {
>> + /* Otherwise, reformat the fpsimd structure into a full SVE set, by
>> + expanding the V registers (working backwards so we don't splat
>> + registers before they are copied) and using zero for everything
>> + else.
>> + Note that enough space for a full SVE dump was originally allocated
>> + for base. */
>> +
>> + header->flags |= SVE_PT_REGS_SVE;
>> + header->size = SVE_PT_SIZE (vq, SVE_PT_REGS_SVE);
>> +
>> + memcpy (base + SVE_PT_SVE_FPSR_OFFSET (vq), &fpsimd->fpsr,
>> + sizeof (uint32_t));
>> + memcpy (base + SVE_PT_SVE_FPCR_OFFSET (vq), &fpsimd->fpcr,
>> + sizeof (uint32_t));
>> +
>> + for (int i = AARCH64_SVE_Z_REGS_NUM; i >= 0 ; i--)
>
> Shouldn't i start from AARCH64_SVE_Z_REGS_NUM - 1? If this is correct, a
> comment explaining why would be helpful.
>
Yes, it should. It seems this slipped through from the previous code. I'll fix it while at it.
Thanks for spotting it!
@@ -319,9 +319,8 @@ store_fpregs_to_thread (const struct regcache *regcache)
static void
fetch_sveregs_from_thread (struct regcache *regcache)
{
- std::unique_ptr<gdb_byte[]> base
- = aarch64_sve_get_sveregs (regcache->ptid ().lwp ());
- aarch64_sve_regs_copy_to_reg_buf (regcache, base.get ());
+ /* Fetch SVE state from the thread and copy it into the register cache. */
+ aarch64_sve_regs_copy_to_reg_buf (regcache->ptid ().lwp (), regcache);
}
/* Store to the current thread the valid sve register
@@ -330,28 +329,9 @@ fetch_sveregs_from_thread (struct regcache *regcache)
static void
store_sveregs_to_thread (struct regcache *regcache)
{
- int ret;
- struct iovec iovec;
- int tid = regcache->ptid ().lwp ();
-
- /* First store vector length to the thread. This is done first to ensure the
- ptrace buffers read from the kernel are the correct size. */
- if (!aarch64_sve_set_vq (tid, regcache))
- perror_with_name (_("Unable to set VG register"));
-
- /* Obtain a dump of SVE registers from ptrace. */
- std::unique_ptr<gdb_byte[]> base = aarch64_sve_get_sveregs (tid);
-
- /* Overwrite with regcache state. */
- aarch64_sve_regs_copy_from_reg_buf (regcache, base.get ());
-
- /* Write back to the kernel. */
- iovec.iov_base = base.get ();
- iovec.iov_len = ((struct user_sve_header *) base.get ())->size;
- ret = ptrace (PTRACE_SETREGSET, tid, NT_ARM_SVE, &iovec);
-
- if (ret < 0)
- perror_with_name (_("Unable to store sve registers"));
+ /* Fetch SVE state from the register cache and update the thread TID with
+ it. */
+ aarch64_sve_regs_copy_from_reg_buf (regcache->ptid ().lwp (), regcache);
}
/* Fill GDB's register array with the pointer authentication mask values from
@@ -120,28 +120,44 @@ aarch64_sve_set_vq (int tid, struct reg_buffer_common *reg_buf)
/* See nat/aarch64-scalable-linux-ptrace.h. */
-std::unique_ptr<gdb_byte[]>
-aarch64_sve_get_sveregs (int tid)
+gdb::byte_vector
+aarch64_fetch_sve_regset (int tid)
{
- struct iovec iovec;
uint64_t vq = aarch64_sve_get_vq (tid);
if (vq == 0)
- perror_with_name (_("Unable to fetch SVE register header"));
+ perror_with_name (_("Unable to fetch SVE vector length"));
/* A ptrace call with NT_ARM_SVE will return a header followed by either a
dump of all the SVE and FP registers, or an fpsimd structure (identical to
the one returned by NT_FPREGSET) if the kernel has not yet executed any
SVE code. Make sure we allocate enough space for a full SVE dump. */
- iovec.iov_len = SVE_PT_SIZE (vq, SVE_PT_REGS_SVE);
- std::unique_ptr<gdb_byte[]> buf (new gdb_byte[iovec.iov_len]);
- iovec.iov_base = buf.get ();
+ gdb::byte_vector sve_state (SVE_PT_SIZE (vq, SVE_PT_REGS_SVE), 0);
+
+ struct iovec iovec;
+ iovec.iov_base = sve_state.data ();
+ iovec.iov_len = sve_state.size ();
if (ptrace (PTRACE_GETREGSET, tid, NT_ARM_SVE, &iovec) < 0)
perror_with_name (_("Unable to fetch SVE registers"));
- return buf;
+ return sve_state;
+}
+
+/* See nat/aarch64-scalable-linux-ptrace.h. */
+
+bool
+aarch64_store_sve_regset (int tid, const gdb::byte_vector &sve_state)
+{
+ struct iovec iovec;
+ iovec.iov_base = (void *) sve_state.data ();
+ iovec.iov_len = sve_state.size ();
+
+ if (ptrace (PTRACE_SETREGSET, tid, NT_ARM_SVE, &iovec) < 0)
+ perror_with_name (_("Unable to store SVE registers"));
+
+ return true;
}
/* If we are running in BE mode, byteswap the contents
@@ -165,11 +181,13 @@ aarch64_maybe_swab128 (gdb_byte *dst, const gdb_byte *src, size_t size)
/* See nat/aarch64-scalable-linux-ptrace.h. */
void
-aarch64_sve_regs_copy_to_reg_buf (struct reg_buffer_common *reg_buf,
- const void *buf)
+aarch64_sve_regs_copy_to_reg_buf (int tid, struct reg_buffer_common *reg_buf)
{
- char *base = (char *) buf;
- struct user_sve_header *header = (struct user_sve_header *) buf;
+ gdb::byte_vector sve_state = aarch64_fetch_sve_regset (tid);
+
+ char *base = (char *) sve_state.data ();
+ struct user_sve_header *header
+ = (struct user_sve_header *) sve_state.data ();
uint64_t vq = sve_vq_from_vl (header->vl);
uint64_t vg = sve_vg_from_vl (header->vl);
@@ -249,18 +267,33 @@ aarch64_sve_regs_copy_to_reg_buf (struct reg_buffer_common *reg_buf,
reg_buf->raw_supply (AARCH64_SVE_FFR_REGNUM, reg);
}
+
+ /* At this point we have updated the register cache with the contents of
+ the NT_ARM_SVE register set. */
}
/* See nat/aarch64-scalable-linux-ptrace.h. */
void
-aarch64_sve_regs_copy_from_reg_buf (const struct reg_buffer_common *reg_buf,
- void *buf)
+aarch64_sve_regs_copy_from_reg_buf (int tid,
+ struct reg_buffer_common *reg_buf)
{
- struct user_sve_header *header = (struct user_sve_header *) buf;
- char *base = (char *) buf;
+ /* First store the vector length to the thread. This is done first to
+ ensure the ptrace buffers read from the kernel are the correct size. */
+ if (!aarch64_sve_set_vq (tid, reg_buf))
+ perror_with_name (_("Unable to set VG register"));
+
+ /* Obtain a dump of SVE registers from ptrace. */
+ gdb::byte_vector sve_state = aarch64_fetch_sve_regset (tid);
+
+ struct user_sve_header *header = (struct user_sve_header *) sve_state.data ();
uint64_t vq = sve_vq_from_vl (header->vl);
+ gdb::byte_vector new_state (SVE_PT_SIZE (32, SVE_PT_REGS_SVE), 0);
+ memcpy (new_state.data (), sve_state.data (), sve_state.size ());
+ header = (struct user_sve_header *) new_state.data ();
+ char *base = (char *) new_state.data ();
+
/* Sanity check the data in the header. */
if (!sve_vl_valid (header->vl)
|| SVE_PT_SIZE (vq, header->flags) != header->size)
@@ -275,36 +308,40 @@ aarch64_sve_regs_copy_from_reg_buf (const struct reg_buffer_common *reg_buf,
resulting in the initialization of SVE state written back to the
kernel, which is why we try to avoid it. */
- bool has_sve_state = false;
- gdb_byte *reg = (gdb_byte *) alloca (SVE_PT_SVE_ZREG_SIZE (vq));
- struct user_fpsimd_state *fpsimd
- = (struct user_fpsimd_state *)(base + SVE_PT_FPSIMD_OFFSET);
-
- memset (reg, 0, SVE_PT_SVE_ZREG_SIZE (vq));
+ /* Buffer (using the maximum size a Z register) used to look for zeroed
+ out sve state. */
+ gdb_byte reg[256];
+ memset (reg, 0, sizeof (reg));
/* Check in the reg_buf if any of the Z registers are set after the
first 128 bits, or if any of the other SVE registers are set. */
-
+ bool has_sve_state = false;
for (int i = 0; i < AARCH64_SVE_Z_REGS_NUM; i++)
{
- has_sve_state |= reg_buf->raw_compare (AARCH64_SVE_Z0_REGNUM + i,
- reg, sizeof (__int128_t));
- if (has_sve_state)
- break;
+ if (!reg_buf->raw_compare (AARCH64_SVE_Z0_REGNUM + i, reg,
+ V_REGISTER_SIZE))
+ {
+ has_sve_state = true;
+ break;
+ }
}
if (!has_sve_state)
for (int i = 0; i < AARCH64_SVE_P_REGS_NUM; i++)
{
- has_sve_state |= reg_buf->raw_compare (AARCH64_SVE_P0_REGNUM + i,
- reg, 0);
- if (has_sve_state)
- break;
+ if (!reg_buf->raw_compare (AARCH64_SVE_P0_REGNUM + i, reg, 0))
+ {
+ has_sve_state = true;
+ break;
+ }
}
if (!has_sve_state)
- has_sve_state |= reg_buf->raw_compare (AARCH64_SVE_FFR_REGNUM,
- reg, 0);
+ has_sve_state
+ = !reg_buf->raw_compare (AARCH64_SVE_FFR_REGNUM, reg, 0);
+
+ struct user_fpsimd_state *fpsimd
+ = (struct user_fpsimd_state *)(base + SVE_PT_FPSIMD_OFFSET);
/* If no SVE state exists, then use the existing fpsimd structure to
write out state and return. */
@@ -344,50 +381,74 @@ aarch64_sve_regs_copy_from_reg_buf (const struct reg_buffer_common *reg_buf,
if (REG_VALID == reg_buf->get_register_status (AARCH64_FPCR_REGNUM))
reg_buf->raw_collect (AARCH64_FPCR_REGNUM, &fpsimd->fpcr);
- return;
- }
-
- /* Otherwise, reformat the fpsimd structure into a full SVE set, by
- expanding the V registers (working backwards so we don't splat
- registers before they are copied) and using null for everything else.
- Note that enough space for a full SVE dump was originally allocated
- for base. */
+ /* At this point we have collected all the data from the register
+ cache and we are ready to update the FPSIMD register content
+ of the thread. */
- header->flags |= SVE_PT_REGS_SVE;
- header->size = SVE_PT_SIZE (vq, SVE_PT_REGS_SVE);
+ /* Fall through so we can update the thread's contents with the
+ FPSIMD register cache values. */
+ }
+ else
+ {
+ /* Otherwise, reformat the fpsimd structure into a full SVE set, by
+ expanding the V registers (working backwards so we don't splat
+ registers before they are copied) and using zero for everything
+ else.
+ Note that enough space for a full SVE dump was originally allocated
+ for base. */
+
+ header->flags |= SVE_PT_REGS_SVE;
+ header->size = SVE_PT_SIZE (vq, SVE_PT_REGS_SVE);
+
+ memcpy (base + SVE_PT_SVE_FPSR_OFFSET (vq), &fpsimd->fpsr,
+ sizeof (uint32_t));
+ memcpy (base + SVE_PT_SVE_FPCR_OFFSET (vq), &fpsimd->fpcr,
+ sizeof (uint32_t));
+
+ for (int i = AARCH64_SVE_Z_REGS_NUM; i >= 0 ; i--)
+ {
+ memcpy (base + SVE_PT_SVE_ZREG_OFFSET (vq, i), &fpsimd->vregs[i],
+ sizeof (__int128_t));
+ }
- memcpy (base + SVE_PT_SVE_FPSR_OFFSET (vq), &fpsimd->fpsr,
- sizeof (uint32_t));
- memcpy (base + SVE_PT_SVE_FPCR_OFFSET (vq), &fpsimd->fpcr,
- sizeof (uint32_t));
+ /* At this point we have converted the FPSIMD layout to an SVE
+ layout and copied the register data.
- for (int i = AARCH64_SVE_Z_REGS_NUM; i >= 0 ; i--)
- {
- memcpy (base + SVE_PT_SVE_ZREG_OFFSET (vq, i), &fpsimd->vregs[i],
- sizeof (__int128_t));
+ Fall through so we can update the thread's contents with the SVE
+ register cache values. */
}
}
+ else
+ {
+ /* We already have SVE state for this thread, so we just need to update
+ the values of the registers. */
+ for (int i = 0; i < AARCH64_SVE_Z_REGS_NUM; i++)
+ if (REG_VALID == reg_buf->get_register_status (AARCH64_SVE_Z0_REGNUM
+ + i))
+ reg_buf->raw_collect (AARCH64_SVE_Z0_REGNUM + i,
+ base + SVE_PT_SVE_ZREG_OFFSET (vq, i));
- /* Replace the kernel values with those from reg_buf. */
-
- for (int i = 0; i < AARCH64_SVE_Z_REGS_NUM; i++)
- if (REG_VALID == reg_buf->get_register_status (AARCH64_SVE_Z0_REGNUM + i))
- reg_buf->raw_collect (AARCH64_SVE_Z0_REGNUM + i,
- base + SVE_PT_SVE_ZREG_OFFSET (vq, i));
-
- for (int i = 0; i < AARCH64_SVE_P_REGS_NUM; i++)
- if (REG_VALID == reg_buf->get_register_status (AARCH64_SVE_P0_REGNUM + i))
- reg_buf->raw_collect (AARCH64_SVE_P0_REGNUM + i,
- base + SVE_PT_SVE_PREG_OFFSET (vq, i));
+ for (int i = 0; i < AARCH64_SVE_P_REGS_NUM; i++)
+ if (REG_VALID == reg_buf->get_register_status (AARCH64_SVE_P0_REGNUM
+ + i))
+ reg_buf->raw_collect (AARCH64_SVE_P0_REGNUM + i,
+ base + SVE_PT_SVE_PREG_OFFSET (vq, i));
+
+ if (REG_VALID == reg_buf->get_register_status (AARCH64_SVE_FFR_REGNUM))
+ reg_buf->raw_collect (AARCH64_SVE_FFR_REGNUM,
+ base + SVE_PT_SVE_FFR_OFFSET (vq));
+ if (REG_VALID == reg_buf->get_register_status (AARCH64_FPSR_REGNUM))
+ reg_buf->raw_collect (AARCH64_FPSR_REGNUM,
+ base + SVE_PT_SVE_FPSR_OFFSET (vq));
+ if (REG_VALID == reg_buf->get_register_status (AARCH64_FPCR_REGNUM))
+ reg_buf->raw_collect (AARCH64_FPCR_REGNUM,
+ base + SVE_PT_SVE_FPCR_OFFSET (vq));
+ }
- if (REG_VALID == reg_buf->get_register_status (AARCH64_SVE_FFR_REGNUM))
- reg_buf->raw_collect (AARCH64_SVE_FFR_REGNUM,
- base + SVE_PT_SVE_FFR_OFFSET (vq));
- if (REG_VALID == reg_buf->get_register_status (AARCH64_FPSR_REGNUM))
- reg_buf->raw_collect (AARCH64_FPSR_REGNUM,
- base + SVE_PT_SVE_FPSR_OFFSET (vq));
- if (REG_VALID == reg_buf->get_register_status (AARCH64_FPCR_REGNUM))
- reg_buf->raw_collect (AARCH64_FPCR_REGNUM,
- base + SVE_PT_SVE_FPCR_OFFSET (vq));
+ /* At this point we have collected all the data from the register cache and
+ we are ready to update the SVE/FPSIMD register contents of the thread.
+ sve_state should contain all the data in the correct format, ready to be
+ passed on to ptrace. */
+ aarch64_store_sve_regset (tid, new_state);
}
@@ -52,22 +52,28 @@ uint64_t aarch64_sve_get_vq (int tid);
bool aarch64_sve_set_vq (int tid, uint64_t vq);
bool aarch64_sve_set_vq (int tid, struct reg_buffer_common *reg_buf);
-/* Read the current SVE register set using ptrace, allocating space as
- required. */
+/* Read the current SVE register set from thread TID and return its data
+ through a byte vector. */
-extern std::unique_ptr<gdb_byte[]> aarch64_sve_get_sveregs (int tid);
+extern gdb::byte_vector aarch64_fetch_sve_regset (int tid);
-/* Put the registers from linux structure buf into register buffer. Assumes the
- vector lengths in the register buffer match the size in the kernel. */
+/* Write the SVE contents from SVE_STATE to thread TID. Return true if
+ successful and false otherwise. */
-extern void aarch64_sve_regs_copy_to_reg_buf (struct reg_buffer_common *reg_buf,
- const void *buf);
+extern bool
+aarch64_store_sve_regset (int tid, const gdb::byte_vector &sve_state);
-/* Put the registers from register buffer into linux structure buf. Assumes the
- vector lengths in the register buffer match the size in the kernel. */
+/* Given a thread id TID and a register buffer REG_BUF, update the register
+ buffer with the SVE state from thread TID. */
extern void
-aarch64_sve_regs_copy_from_reg_buf (const struct reg_buffer_common *reg_buf,
- void *buf);
+aarch64_sve_regs_copy_to_reg_buf (int tid, struct reg_buffer_common *reg_buf);
+
+/* Given a thread id TID and a register buffer REG_BUF containing SVE
+ register data, write the SVE data to thread TID. */
+
+extern void
+aarch64_sve_regs_copy_from_reg_buf (int tid,
+ struct reg_buffer_common *reg_buf);
#endif /* NAT_AARCH64_SCALABLE_LINUX_PTRACE_H */
@@ -719,9 +719,18 @@ aarch64_target::low_new_fork (process_info *parent,
/* Wrapper for aarch64_sve_regs_copy_to_reg_buf. */
static void
-aarch64_sve_regs_copy_to_regcache (struct regcache *regcache, const void *buf)
+aarch64_sve_regs_copy_to_regcache (struct regcache *regcache,
+ ATTRIBUTE_UNUSED const void *buf)
{
- return aarch64_sve_regs_copy_to_reg_buf (regcache, buf);
+ /* BUF is unused here since we collect the data straight from a ptrace
+ request in aarch64_sve_regs_copy_to_reg_buf, therefore bypassing
+ gdbserver's own call to ptrace. */
+
+ int tid = lwpid_of (current_thread);
+
+ /* Update the register cache. aarch64_sve_regs_copy_to_reg_buf handles
+ fetching the NT_ARM_SVE state from thread TID. */
+ aarch64_sve_regs_copy_to_reg_buf (tid, regcache);
}
/* Wrapper for aarch64_sve_regs_copy_from_reg_buf. */
@@ -729,7 +738,16 @@ aarch64_sve_regs_copy_to_regcache (struct regcache *regcache, const void *buf)
static void
aarch64_sve_regs_copy_from_regcache (struct regcache *regcache, void *buf)
{
- return aarch64_sve_regs_copy_from_reg_buf (regcache, buf);
+ int tid = lwpid_of (current_thread);
+
+ /* Update the thread SVE state. aarch64_sve_regs_copy_from_reg_buf
+ handles writing the SVE/FPSIMD state back to thread TID. */
+ aarch64_sve_regs_copy_from_reg_buf (tid, regcache);
+
+ /* We need to return the expected data in BUF, so copy whatever the kernel
+ already has to BUF. */
+ gdb::byte_vector sve_state = aarch64_fetch_sve_regset (tid);
+ memcpy (buf, sve_state.data (), sve_state.size ());
}
/* Array containing all the possible register sets for AArch64/Linux. During