Ptrace support for Aarch64 SVEusers/simark/regcache-for-alan

Add support for reading and writing registers for Aarch64 SVE.
I've made this functionality common as it will be required for
gdbserver when gdbsever sve support is added.

Given that gdbserver does not yet call this function, I am
happy to remove the regcache commonise functions from the
previous patch. However, this would result in code in nat/
that does not compile for gdbserver. I wanted to avoid that.

We need to support the cases where the kernel only gives us a
fpsimd structure. This occurs when there is no active SVE state
in the kernel (for example, after starting a new process).

As per the covering email description, I've included large chunks
of linux kernel headers within an ifdef. Formatting of these macros
remains identical to the Kernel versions (ie not adapted to GNU style).

Added checks to make sure the vector length has not changed whilst
the process is running.

2018-05-11  Alan Hayward  <alan.hayward@arm.com>

gdb/
	* aarch64-linux-nat.c (fetch_sveregs_from_thread): New function.
	(store_sveregs_to_thread): Likewise.
	(aarch64_linux_fetch_inferior_registers): Check for SVE.
	(aarch64_linux_store_inferior_registers): Likewise.
	* nat/aarch64-sve-linux-ptrace.c (aarch64_sve_get_sveregs): New
	function.
	(aarch64_sve_regs_copy_to_regcache): Likewise.
	(aarch64_sve_regs_copy_from_regcache): Likewise.
	* nat/aarch64-sve-linux-ptrace.h (aarch64_sve_get_sveregs): New
	declaration.
	(aarch64_sve_regs_copy_to_regcache): Likewise.
	(aarch64_sve_regs_copy_from_regcache): Likewise.
	(sve_context): Structure from Linux headers.
	(SVE_SIG_ZREGS_SIZE): Define from Linux headers.
	(SVE_SIG_ZREG_SIZE): Likewise.
	(SVE_SIG_PREG_SIZE): Likewise.
	(SVE_SIG_FFR_SIZE): Likewise.
	(SVE_SIG_REGS_OFFSET): Likewise.
	(SVE_SIG_ZREGS_OFFSET): Likewise.
	(SVE_SIG_ZREG_OFFSET): Likewise.
	(SVE_SIG_ZREGS_SIZE): Likewise.
	(SVE_SIG_PREGS_OFFSET): Likewise.
	(SVE_SIG_PREG_OFFSET): Likewise.
	(SVE_SIG_PREGS_SIZE): Likewise.
	(SVE_SIG_FFR_OFFSET): Likewise.
	(SVE_SIG_REGS_SIZE): Likewise.
	(SVE_SIG_CONTEXT_SIZE): Likewise.
	(SVE_PT_REGS_MASK): Likewise.
	(SVE_PT_REGS_FPSIMD): Likewise.
	(SVE_PT_REGS_SVE): Likewise.
	(SVE_PT_VL_INHERIT): Likewise.
	(SVE_PT_VL_ONEXEC): Likewise.
	(SVE_PT_REGS_OFFSET): Likewise.
	(SVE_PT_FPSIMD_OFFSET): Likewise.
	(SVE_PT_FPSIMD_SIZE): Likewise.
	(SVE_PT_SVE_ZREG_SIZE): Likewise.
	(SVE_PT_SVE_PREG_SIZE): Likewise.
	(SVE_PT_SVE_FFR_SIZE): Likewise.
	(SVE_PT_SVE_FPSR_SIZE): Likewise.
	(SVE_PT_SVE_FPCR_SIZE): Likewise.
	(__SVE_SIG_TO_PT): Likewise.
	(SVE_PT_SVE_OFFSET): Likewise.
	(SVE_PT_SVE_ZREGS_OFFSET): Likewise.
	(SVE_PT_SVE_ZREG_OFFSET): Likewise.
	(SVE_PT_SVE_ZREGS_SIZE): Likewise.
	(SVE_PT_SVE_PREGS_OFFSET): Likewise.
	(SVE_PT_SVE_PREG_OFFSET): Likewise.
	(SVE_PT_SVE_PREGS_SIZE): Likewise.
	(SVE_PT_SVE_FFR_OFFSET): Likewise.
	(SVE_PT_SVE_FPSR_OFFSET): Likewise.
	(SVE_PT_SVE_FPCR_OFFSET): Likewise.
	(SVE_PT_SVE_SIZE): Likewise.
	(SVE_PT_SIZE): Likewise.
	(HAS_SVE_STATE): New define.

gdbserver
	* Makefile.in: Add aarch64-sve-linux-ptrace.c.

1 files changed, 5 insertions, 5 deletions

diff --git a/gdb/regcache.h b/gdb/regcache.h
index 432e1b3..f271775 100644
--- a/gdb/regcache.h
+++ b/gdb/regcache.h
@@ -121,7 +121,7 @@ typedef struct cached_reg
 
 /* Buffer of registers.  */
 
-class reg_buffer
+class reg_buffer : public reg_buffer_common
 {
 public:
   reg_buffer (gdbarch *gdbarch, bool has_pseudo);
@@ -133,10 +133,10 @@ public:
 
   /* Get the availability status of the value of register REGNUM in this
      buffer.  */
-  enum register_status get_register_status (int regnum) const;
+  enum register_status get_register_status (int regnum) const override;
 
   /* Collect register REGNUM from REGCACHE and store its contents in BUF.  */
-  void raw_collect (int regnum, void *buf) const;
+  void raw_collect (int regnum, void *buf) const override;
 
   void raw_collect_integer (int regnum, gdb_byte *addr, int addr_len,
 			    bool is_signed) const;
@@ -145,7 +145,7 @@ public:
 		       void *buf, size_t size) const;
 
   /* Supply register REGNUM, whose contents are stored in BUF, to REGCACHE.  */
-  void raw_supply (int regnum, const void *buf);
+  void raw_supply (int regnum, const void *buf) override;
 
   void raw_supply (int regnum, const reg_buffer &src)
   {
@@ -162,7 +162,7 @@ public:
 
   void invalidate (int regnum);
 
-  int raw_compare (int regnum, const void *buf, int offset) const;
+  bool raw_compare (int regnum, const void *buf, int offset) const override;
 
   /* Dump the contents of a register from the register cache to the target
      debug.  */