[PATCH v2 02/10] Add Aarch64 SVE Linux headers

Alan Hayward
2018-06-06T15:17:07Z

Take all the new SVE defines/structures in the Linux kernel from sigcontext.h
and ptrace.h, placing into their own files. Those parts that already existed
in gdb codebase have been moved to the new files.

Contents are copied directly without any formatting changes.

Copied from the release tag for Linux 4.17

This change ensures gdb can still be built using older Linux kernel headers.

Confirmed builds with both new and old headers.

2018-06-06 Alan Hayward <alan.hayward@arm.com>

* aarch64-tdep.c: Add include
* arch/aarch64.h (sve_vq_from_vl): Remove
(sve_vl_from_vq): Likewise.
* nat/aarch64-linux-ptrace.h: New file.
* nat/aarch64-linux-sigcontext.h: New file.
* nat/aarch64-sve-linux-ptrace.h (aarch64_sve_get_vq): Move to
new files.
(SVE_VQ_BYTES): Likewise.
(SVE_VQ_MIN): Likewise.
(SVE_VQ_MAX): Likewise.
(SVE_VL_MIN): Likewise.
(SVE_VL_MAX): Likewise.
(SVE_NUM_ZREGS): Likewise.
(SVE_NUM_PREGS): Likewise.
(sve_vl_valid): Likewise.
(struct user_sve_header): Likewise.
---
gdb/aarch64-tdep.c | 1 +
gdb/arch/aarch64.h | 5 +-
gdb/nat/aarch64-linux-ptrace.h | 150 +++++++++++++++++++++++++++++++++++++
gdb/nat/aarch64-linux-sigcontext.h | 129 +++++++++++++++++++++++++++++++
gdb/nat/aarch64-sve-linux-ptrace.h | 46 ++----------
5 files changed, 289 insertions(+), 42 deletions(-)
create mode 100644 gdb/nat/aarch64-linux-ptrace.h
create mode 100644 gdb/nat/aarch64-linux-sigcontext.h

diff --git a/gdb/aarch64-tdep.c b/gdb/aarch64-tdep.c
index 2fe6a4006c..0438ab83cd 100644
--- a/gdb/aarch64-tdep.c
+++ b/gdb/aarch64-tdep.c
@@ -58,6 +58,7 @@

#include "opcode/aarch64.h"
#include <algorithm>
+#include "nat/aarch64-sve-linux-ptrace.h"

#define submask(x) ((1L << ((x) + 1)) - 1)
#define bit(obj,st) (((obj) >> (st)) & 1)
diff --git a/gdb/arch/aarch64.h b/gdb/arch/aarch64.h
index 9040d8d4c8..04e41f71df 100644
--- a/gdb/arch/aarch64.h
+++ b/gdb/arch/aarch64.h
@@ -76,11 +76,10 @@ enum aarch64_regnum

#define sve_vg_from_vl(vl) ((vl) / 8)
#define sve_vl_from_vg(vg) ((vg) * 8)
-#define sve_vq_from_vl(vl) ((vl) / 0x10)
-#define sve_vl_from_vq(vq) ((vq) * 0x10)
#define sve_vq_from_vg(vg) (sve_vq_from_vl (sve_vl_from_vg (vg)))
#define sve_vg_from_vq(vq) (sve_vg_from_vl (sve_vl_from_vq (vq)))
-
+/* sve_vq_from_vl(vl) : see nat/aarch64-linux-sigcontext.h
+ sve_vl_from_vq(vq) : see nat/aarch64-linux-sigcontext.h. */

/* Maximum supported VQ value. Increase if required. */
#define AARCH64_MAX_SVE_VQ 16
diff --git a/gdb/nat/aarch64-linux-ptrace.h b/gdb/nat/aarch64-linux-ptrace.h
new file mode 100644
index 0000000000..1d0bf1b314
--- /dev/null
+++ b/gdb/nat/aarch64-linux-ptrace.h
@@ -0,0 +1,150 @@
+/* This file contains Aarch64 Linux ptrace defines. It is required for those
+ compiling with older kernel headers. Eventually, when the kernel defines are
+ old enough, this file should be removed.
+
+ Contents are directly copied directly from
+ linux/arch/arm64/include/uapi/asm/ptrace.h in Linux 4.17.
+
+ See:
+ https://github.com/torvalds/linux/blob/v4.17/arch/arm64/include/uapi/asm/ptrace.h
+*/
+
+#ifndef AARCH64_LINUX_PTRACE_H
+#define AARCH64_LINUX_PTRACE_H
+
+/* SVE/FP/SIMD state (NT_ARM_SVE) */
+
+struct user_sve_header {
+ __u32 size; /* total meaningful regset content in bytes */
+ __u32 max_size; /* maxmium possible size for this thread */
+ __u16 vl; /* current vector length */
+ __u16 max_vl; /* maximum possible vector length */
+ __u16 flags;
+ __u16 __reserved;
+};
+
+/* Definitions for user_sve_header.flags: */
+#define SVE_PT_REGS_MASK (1 << 0)
+
+#define SVE_PT_REGS_FPSIMD 0
+#define SVE_PT_REGS_SVE SVE_PT_REGS_MASK
+
+/*
+ * Common SVE_PT_* flags:
+ * These must be kept in sync with prctl interface in <linux/ptrace.h>
+ */
+#define SVE_PT_VL_INHERIT (PR_SVE_VL_INHERIT >> 16)
+#define SVE_PT_VL_ONEXEC (PR_SVE_SET_VL_ONEXEC >> 16)
+
+
+/*
+ * The remainder of the SVE state follows struct user_sve_header. The
+ * total size of the SVE state (including header) depends on the
+ * metadata in the header: SVE_PT_SIZE(vq, flags) gives the total size
+ * of the state in bytes, including the header.
+ *
+ * Refer to <asm/sigcontext.h> for details of how to pass the correct
+ * "vq" argument to these macros.
+ */
+
+/* Offset from the start of struct user_sve_header to the register data */
+#define SVE_PT_REGS_OFFSET \
+ ((sizeof(struct sve_context) + (SVE_VQ_BYTES - 1)) \
+ / SVE_VQ_BYTES * SVE_VQ_BYTES)
+
+/*
+ * The register data content and layout depends on the value of the
+ * flags field.
+ */
+
+/*
+ * (flags & SVE_PT_REGS_MASK) == SVE_PT_REGS_FPSIMD case:
+ *
+ * The payload starts at offset SVE_PT_FPSIMD_OFFSET, and is of type
+ * struct user_fpsimd_state. Additional data might be appended in the
+ * future: use SVE_PT_FPSIMD_SIZE(vq, flags) to compute the total size.
+ * SVE_PT_FPSIMD_SIZE(vq, flags) will never be less than
+ * sizeof(struct user_fpsimd_state).
+ */
+
+#define SVE_PT_FPSIMD_OFFSET SVE_PT_REGS_OFFSET
+
+#define SVE_PT_FPSIMD_SIZE(vq, flags) (sizeof(struct user_fpsimd_state))
+
+/*
+ * (flags & SVE_PT_REGS_MASK) == SVE_PT_REGS_SVE case:
+ *
+ * The payload starts at offset SVE_PT_SVE_OFFSET, and is of size
+ * SVE_PT_SVE_SIZE(vq, flags).
+ *
+ * Additional macros describe the contents and layout of the payload.
+ * For each, SVE_PT_SVE_x_OFFSET(args) is the start offset relative to
+ * the start of struct user_sve_header, and SVE_PT_SVE_x_SIZE(args) is
+ * the size in bytes:
+ *
+ * x type description
+ * - ---- -----------
+ * ZREGS \
+ * ZREG |
+ * PREGS | refer to <asm/sigcontext.h>
+ * PREG |
+ * FFR /
+ *
+ * FPSR uint32_t FPSR
+ * FPCR uint32_t FPCR
+ *
+ * Additional data might be appended in the future.
+ */
+
+#define SVE_PT_SVE_ZREG_SIZE(vq) SVE_SIG_ZREG_SIZE(vq)
+#define SVE_PT_SVE_PREG_SIZE(vq) SVE_SIG_PREG_SIZE(vq)
+#define SVE_PT_SVE_FFR_SIZE(vq) SVE_SIG_FFR_SIZE(vq)
+#define SVE_PT_SVE_FPSR_SIZE sizeof(__u32)
+#define SVE_PT_SVE_FPCR_SIZE sizeof(__u32)
+
+#define __SVE_SIG_TO_PT(offset) \
+ ((offset) - SVE_SIG_REGS_OFFSET + SVE_PT_REGS_OFFSET)
+
+#define SVE_PT_SVE_OFFSET SVE_PT_REGS_OFFSET
+
+#define SVE_PT_SVE_ZREGS_OFFSET \
+ __SVE_SIG_TO_PT(SVE_SIG_ZREGS_OFFSET)
+#define SVE_PT_SVE_ZREG_OFFSET(vq, n) \
+ __SVE_SIG_TO_PT(SVE_SIG_ZREG_OFFSET(vq, n))
+#define SVE_PT_SVE_ZREGS_SIZE(vq) \
+ (SVE_PT_SVE_ZREG_OFFSET(vq, SVE_NUM_ZREGS) - SVE_PT_SVE_ZREGS_OFFSET)
+
+#define SVE_PT_SVE_PREGS_OFFSET(vq) \
+ __SVE_SIG_TO_PT(SVE_SIG_PREGS_OFFSET(vq))
+#define SVE_PT_SVE_PREG_OFFSET(vq, n) \
+ __SVE_SIG_TO_PT(SVE_SIG_PREG_OFFSET(vq, n))
+#define SVE_PT_SVE_PREGS_SIZE(vq) \
+ (SVE_PT_SVE_PREG_OFFSET(vq, SVE_NUM_PREGS) - \
+ SVE_PT_SVE_PREGS_OFFSET(vq))
+
+#define SVE_PT_SVE_FFR_OFFSET(vq) \
+ __SVE_SIG_TO_PT(SVE_SIG_FFR_OFFSET(vq))
+
+#define SVE_PT_SVE_FPSR_OFFSET(vq) \
+ ((SVE_PT_SVE_FFR_OFFSET(vq) + SVE_PT_SVE_FFR_SIZE(vq) + \
+ (SVE_VQ_BYTES - 1)) \
+ / SVE_VQ_BYTES * SVE_VQ_BYTES)
+#define SVE_PT_SVE_FPCR_OFFSET(vq) \
+ (SVE_PT_SVE_FPSR_OFFSET(vq) + SVE_PT_SVE_FPSR_SIZE)
+
+/*
+ * Any future extension appended after FPCR must be aligned to the next
+ * 128-bit boundary.
+ */
+
+#define SVE_PT_SVE_SIZE(vq, flags) \
+ ((SVE_PT_SVE_FPCR_OFFSET(vq) + SVE_PT_SVE_FPCR_SIZE \
+ - SVE_PT_SVE_OFFSET + (SVE_VQ_BYTES - 1)) \
+ / SVE_VQ_BYTES * SVE_VQ_BYTES)
+
+#define SVE_PT_SIZE(vq, flags) \
+ (((flags) & SVE_PT_REGS_MASK) == SVE_PT_REGS_SVE ? \
+ SVE_PT_SVE_OFFSET + SVE_PT_SVE_SIZE(vq, flags) \
+ : SVE_PT_FPSIMD_OFFSET + SVE_PT_FPSIMD_SIZE(vq, flags))
+
+#endif /* AARCH64_LINUX_PTRACE_H */
diff --git a/gdb/nat/aarch64-linux-sigcontext.h b/gdb/nat/aarch64-linux-sigcontext.h
new file mode 100644
index 0000000000..5dc1b7db3f
--- /dev/null
+++ b/gdb/nat/aarch64-linux-sigcontext.h
@@ -0,0 +1,129 @@
+/* This file contains Aarch64 Linux sigcontext defines. It is required for those
+ compiling with older kernel headers. Eventually, when the kernel defines are
+ old enough, this file should be removed.
+
+ Contents are directly copied directly from
+ linux/arch/arm64/include/uapi/asm/sigcontext.h in Linux 4.17.
+
+ See:
+ https://github.com/torvalds/linux/blob/v4.17/arch/arm64/include/uapi/asm/sigcontext.h
+*/
+
+#ifndef AARCH64_LINUX_SIGCONTEXT_H
+#define AARCH64_LINUX_SIGCONTEXT_H
+
+
+#define SVE_MAGIC 0x53564501
+
+struct sve_context {
+ struct _aarch64_ctx head;
+ __u16 vl;
+ __u16 __reserved[3];
+};
+
+/*
+ * The SVE architecture leaves space for future expansion of the
+ * vector length beyond its initial architectural limit of 2048 bits
+ * (16 quadwords).
+ *
+ * See linux/Documentation/arm64/sve.txt for a description of the VL/VQ
+ * terminology.
+ */
+#define SVE_VQ_BYTES 16 /* number of bytes per quadword */
+
+#define SVE_VQ_MIN 1
+#define SVE_VQ_MAX 512
+
+#define SVE_VL_MIN (SVE_VQ_MIN * SVE_VQ_BYTES)
+#define SVE_VL_MAX (SVE_VQ_MAX * SVE_VQ_BYTES)
+
+#define SVE_NUM_ZREGS 32
+#define SVE_NUM_PREGS 16
+
+#define sve_vl_valid(vl) \
+ ((vl) % SVE_VQ_BYTES == 0 && (vl) >= SVE_VL_MIN && (vl) <= SVE_VL_MAX)
+#define sve_vq_from_vl(vl) ((vl) / SVE_VQ_BYTES)
+#define sve_vl_from_vq(vq) ((vq) * SVE_VQ_BYTES)
+
+/*
+ * If the SVE registers are currently live for the thread at signal delivery,
+ * sve_context.head.size >=
+ * SVE_SIG_CONTEXT_SIZE(sve_vq_from_vl(sve_context.vl))
+ * and the register data may be accessed using the SVE_SIG_*() macros.
+ *
+ * If sve_context.head.size <
+ * SVE_SIG_CONTEXT_SIZE(sve_vq_from_vl(sve_context.vl)),
+ * the SVE registers were not live for the thread and no register data
+ * is included: in this case, the SVE_SIG_*() macros should not be
+ * used except for this check.
+ *
+ * The same convention applies when returning from a signal: a caller
+ * will need to remove or resize the sve_context block if it wants to
+ * make the SVE registers live when they were previously non-live or
+ * vice-versa. This may require the the caller to allocate fresh
+ * memory and/or move other context blocks in the signal frame.
+ *
+ * Changing the vector length during signal return is not permitted:
+ * sve_context.vl must equal the thread's current vector length when
+ * doing a sigreturn.
+ *
+ *
+ * Note: for all these macros, the "vq" argument denotes the SVE
+ * vector length in quadwords (i.e., units of 128 bits).
+ *
+ * The correct way to obtain vq is to use sve_vq_from_vl(vl). The
+ * result is valid if and only if sve_vl_valid(vl) is true. This is
+ * guaranteed for a struct sve_context written by the kernel.
+ *
+ *
+ * Additional macros describe the contents and layout of the payload.
+ * For each, SVE_SIG_x_OFFSET(args) is the start offset relative to
+ * the start of struct sve_context, and SVE_SIG_x_SIZE(args) is the
+ * size in bytes:
+ *
+ * x type description
+ * - ---- -----------
+ * REGS the entire SVE context
+ *
+ * ZREGS __uint128_t[SVE_NUM_ZREGS][vq] all Z-registers
+ * ZREG __uint128_t[vq] individual Z-register Zn
+ *
+ * PREGS uint16_t[SVE_NUM_PREGS][vq] all P-registers
+ * PREG uint16_t[vq] individual P-register Pn
+ *
+ * FFR uint16_t[vq] first-fault status register
+ *
+ * Additional data might be appended in the future.
+ */
+
+#define SVE_SIG_ZREG_SIZE(vq) ((__u32)(vq) * SVE_VQ_BYTES)
+#define SVE_SIG_PREG_SIZE(vq) ((__u32)(vq) * (SVE_VQ_BYTES / 8))
+#define SVE_SIG_FFR_SIZE(vq) SVE_SIG_PREG_SIZE(vq)
+
+#define SVE_SIG_REGS_OFFSET \
+ ((sizeof(struct sve_context) + (SVE_VQ_BYTES - 1)) \
+ / SVE_VQ_BYTES * SVE_VQ_BYTES)
+
+#define SVE_SIG_ZREGS_OFFSET SVE_SIG_REGS_OFFSET
+#define SVE_SIG_ZREG_OFFSET(vq, n) \
+ (SVE_SIG_ZREGS_OFFSET + SVE_SIG_ZREG_SIZE(vq) * (n))
+#define SVE_SIG_ZREGS_SIZE(vq) \
+ (SVE_SIG_ZREG_OFFSET(vq, SVE_NUM_ZREGS) - SVE_SIG_ZREGS_OFFSET)
+
+#define SVE_SIG_PREGS_OFFSET(vq) \
+ (SVE_SIG_ZREGS_OFFSET + SVE_SIG_ZREGS_SIZE(vq))
+#define SVE_SIG_PREG_OFFSET(vq, n) \
+ (SVE_SIG_PREGS_OFFSET(vq) + SVE_SIG_PREG_SIZE(vq) * (n))
+#define SVE_SIG_PREGS_SIZE(vq) \
+ (SVE_SIG_PREG_OFFSET(vq, SVE_NUM_PREGS) - SVE_SIG_PREGS_OFFSET(vq))
+
+#define SVE_SIG_FFR_OFFSET(vq) \
+ (SVE_SIG_PREGS_OFFSET(vq) + SVE_SIG_PREGS_SIZE(vq))
+
+#define SVE_SIG_REGS_SIZE(vq) \
+ (SVE_SIG_FFR_OFFSET(vq) + SVE_SIG_FFR_SIZE(vq) - SVE_SIG_REGS_OFFSET)
+
+#define SVE_SIG_CONTEXT_SIZE(vq) (SVE_SIG_REGS_OFFSET + SVE_SIG_REGS_SIZE(vq))
+
+
+#endif /* AARCH64_LINUX_SIGCONTEXT_H */
diff --git a/gdb/nat/aarch64-sve-linux-ptrace.h b/gdb/nat/aarch64-sve-linux-ptrace.h
index 61f841466c..2d6f5714c0 100644
--- a/gdb/nat/aarch64-sve-linux-ptrace.h
+++ b/gdb/nat/aarch64-sve-linux-ptrace.h
@@ -20,54 +20,22 @@
#ifndef AARCH64_SVE_LINUX_PTRACE_H
#define AARCH64_SVE_LINUX_PTRACE_H

-/* Where indicated, this file contains defines and macros lifted directly from
- the Linux kernel headers, with no modification.
- Refer to Linux kernel documentation for details. */
-
#include <asm/sigcontext.h>
#include <sys/utsname.h>
#include <sys/ptrace.h>
#include <asm/ptrace.h>

-/* Read VQ for the given tid using ptrace. If SVE is not supported then zero
- is returned (on a system that supports SVE, then VQ cannot be zero). */
-
-uint64_t aarch64_sve_get_vq (int tid);
-
-/* Structures and defines taken from sigcontext.h. */
-
#ifndef SVE_SIG_ZREGS_SIZE
-
-#define SVE_VQ_BYTES 16 /* number of bytes per quadword */
-
-#define SVE_VQ_MIN 1
-#define SVE_VQ_MAX 512
-
-#define SVE_VL_MIN (SVE_VQ_MIN * SVE_VQ_BYTES)
-#define SVE_VL_MAX (SVE_VQ_MAX * SVE_VQ_BYTES)
-
-#define SVE_NUM_ZREGS 32
-#define SVE_NUM_PREGS 16
-
-#define sve_vl_valid(vl) \
- ((vl) % SVE_VQ_BYTES == 0 && (vl) >= SVE_VL_MIN && (vl) <= SVE_VL_MAX)
-
-#endif /* SVE_SIG_ZREGS_SIZE. */
-
-
-/* Structures and defines taken from ptrace.h. */
+#include "aarch64-linux-sigcontext.h"
+#endif

#ifndef SVE_PT_SVE_ZREG_SIZE
+#include "aarch64-linux-ptrace.h"
+#endif

-struct user_sve_header {
- __u32 size; /* total meaningful regset content in bytes */
- __u32 max_size; /* maxmium possible size for this thread */
- __u16 vl; /* current vector length */
- __u16 max_vl; /* maximum possible vector length */
- __u16 flags;
- __u16 __reserved;
-};
+/* Read VQ for the given tid using ptrace. If SVE is not supported then zero
+ is returned (on a system that supports SVE, then VQ cannot be zero). */

-#endif /* SVE_PT_SVE_ZREG_SIZE. */
+uint64_t aarch64_sve_get_vq (int tid);

#endif /* aarch64-sve-linux-ptrace.h */
--
2.15.1 (Apple Git-101)