diff mbox

[1/2] Add linux_get_hwcap

Message ID 20190325120542.92123-1-alan.hayward@arm.com
State New
Headers show

Commit Message

Alan Hayward March 25, 2019, 12:05 p.m. UTC
Tidy up calls to read HWCAP (and HWCAP2) by adding common functions,
removing the PPC and AArch64 specific versions.

The only function difference is in aarch64_linux_core_read_description - if
the hwcap read fails it now return a valid description instead of nullptr.

Tested using AArch64, making sure PAUTH is detected correctly.

gdb/ChangeLog:

2019-03-25  Alan Hayward  <alan.hayward@arm.com>

	* aarch64-linux-nat.c (aarch64_linux_nat_target::read_description):
	Call linux_get_hwcap.
	* aarch64-linux-tdep.c (aarch64_linux_core_read_description):
	Likewise.
	(aarch64_linux_get_hwcap): Remove function.
	* aarch64-linux-tdep.h (aarch64_linux_get_hwcap): Remove
	declaration.
	* arm-linux-nat.c (arm_linux_nat_target::read_description):Call
	linux_get_hwcap.
	* arm-linux-tdep.c (arm_linux_core_read_description): Likewise.
	* linux-tdep.c (linux_get_hwcap): Add function.
	(linux_get_hwcap2): Likewise.
	* linux-tdep.h (linux_get_hwcap): Add declaration.
	(linux_get_hwcap2): Likewise.
	* ppc-linux-nat.c (ppc_linux_get_hwcap): Remove function.
	(ppc_linux_get_hwcap2): Likewise.
	(ppc_linux_nat_target::region_ok_for_hw_watchpoint): Call
	linux_get_hwcap.
	(ppc_linux_nat_target::insert_watchpoint): Likewise.
	(ppc_linux_nat_target::watchpoint_addr_within_range): Likewise.
	(ppc_linux_nat_target::read_description): Likewise.
	* ppc-linux-tdep.c (ppc_linux_core_read_description): Likewise.
	* s390-linux-nat.c: Likewise.
	* s390-linux-tdep.c (s390_core_read_description): Likewise.
---
 gdb/aarch64-linux-nat.c  |  8 ++++----
 gdb/aarch64-linux-tdep.c | 16 ++--------------
 gdb/aarch64-linux-tdep.h |  3 ---
 gdb/arm-linux-nat.c      |  7 +------
 gdb/arm-linux-tdep.c     |  5 +----
 gdb/linux-tdep.c         | 22 ++++++++++++++++++++++
 gdb/linux-tdep.h         |  6 ++++++
 gdb/ppc-linux-nat.c      | 39 +++++++--------------------------------
 gdb/ppc-linux-tdep.c     |  5 +----
 gdb/s390-linux-nat.c     |  3 +--
 gdb/s390-linux-tdep.c    |  3 +--
 11 files changed, 46 insertions(+), 71 deletions(-)

Comments

Simon Marchi March 25, 2019, 3:18 p.m. UTC | #1
On 2019-03-25 8:05 a.m., Alan Hayward wrote:
> Tidy up calls to read HWCAP (and HWCAP2) by adding common functions,
> removing the PPC and AArch64 specific versions.
> 
> The only function difference is in aarch64_linux_core_read_description - if
> the hwcap read fails it now return a valid description instead of nullptr.

ARM also seems to have changed behavior, both the native target and core 
target.  It's not necessarily, a problem, as long as it's a conscious 
change.

> diff --git a/gdb/linux-tdep.h b/gdb/linux-tdep.h
> index 824ba3afaf..ee9c2bcc90 100644
> --- a/gdb/linux-tdep.h
> +++ b/gdb/linux-tdep.h
> @@ -61,4 +61,10 @@ extern void linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch);
>   
>   extern int linux_is_uclinux (void);
>   
> +/* Fetch the AT_HWCAP entry from the auxv vector for the given TARGET.  */
> +extern CORE_ADDR linux_get_hwcap (struct target_ops *target);
> +
> +/* Fetch the AT_HWCAP2 entry from the auxv vector for the given TARGET.  */
> +extern CORE_ADDR linux_get_hwcap2 (struct target_ops *target);

For these two functions, can you mention that 0 is returned if the 
search in the AUXV vector fails?

I was a bit surprised you didn't keep your version returning a bool to 
indicate whether the search succeeded or failed, but if this version is 
good enough, I am fine with it.  If we ever have a target that really 
needs to differentiate between a lookup failure and a lookup success 
that returns the value 0, we can change it back or add another overload.

This patch LGTM with the comment above updated.

Simon
diff mbox

Patch

diff --git a/gdb/aarch64-linux-nat.c b/gdb/aarch64-linux-nat.c
index 86c7e87dd5..6d43eb7070 100644
--- a/gdb/aarch64-linux-nat.c
+++ b/gdb/aarch64-linux-nat.c
@@ -42,6 +42,7 @@ 
 #include <asm/ptrace.h>
 
 #include "gregset.h"
+#include "linux-tdep.h"
 
 /* Defines ps_err_e, struct ps_prochandle.  */
 #include "gdb_proc_service.h"
@@ -641,11 +642,10 @@  aarch64_linux_nat_target::read_description ()
   if (ret == 0)
     return tdesc_arm_with_neon;
 
-  CORE_ADDR hwcap = 0;
-  bool pauth_p = aarch64_linux_get_hwcap (this, &hwcap)
-		 && (hwcap & AARCH64_HWCAP_PACA);
+  CORE_ADDR hwcap = linux_get_hwcap (this);
 
-  return aarch64_read_description (aarch64_sve_get_vq (tid), pauth_p);
+  return aarch64_read_description (aarch64_sve_get_vq (tid),
+				   hwcap & AARCH64_HWCAP_PACA);
 }
 
 /* Convert a native/host siginfo object, into/from the siginfo in the
diff --git a/gdb/aarch64-linux-tdep.c b/gdb/aarch64-linux-tdep.c
index bcd1961744..7f2193f2fa 100644
--- a/gdb/aarch64-linux-tdep.c
+++ b/gdb/aarch64-linux-tdep.c
@@ -655,13 +655,10 @@  static const struct target_desc *
 aarch64_linux_core_read_description (struct gdbarch *gdbarch,
 				     struct target_ops *target, bfd *abfd)
 {
-  CORE_ADDR aarch64_hwcap = 0;
-
-  if (!aarch64_linux_get_hwcap (target, &aarch64_hwcap))
-    return nullptr;
+  CORE_ADDR hwcap = linux_get_hwcap (target);
 
   return aarch64_read_description (aarch64_linux_core_read_vq (gdbarch, abfd),
-				   aarch64_hwcap & AARCH64_HWCAP_PACA);
+				   hwcap & AARCH64_HWCAP_PACA);
 }
 
 /* Implementation of `gdbarch_stap_is_single_operand', as defined in
@@ -1439,15 +1436,6 @@  aarch64_linux_gcc_target_options (struct gdbarch *gdbarch)
   return NULL;
 }
 
-/* See aarch64-linux-tdep.h.  */
-
-bool
-aarch64_linux_get_hwcap (struct target_ops *target, CORE_ADDR *hwcap)
-{
-  *hwcap = 0;
-  return target_auxv_search (target, AT_HWCAP, hwcap) == 1;
-}
-
 static void
 aarch64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
diff --git a/gdb/aarch64-linux-tdep.h b/gdb/aarch64-linux-tdep.h
index ec494bfc53..f075f0acd9 100644
--- a/gdb/aarch64-linux-tdep.h
+++ b/gdb/aarch64-linux-tdep.h
@@ -42,7 +42,4 @@  extern const struct regset aarch64_linux_fpregset;
 /* Matches HWCAP_PACA in kernel header arch/arm64/include/uapi/asm/hwcap.h.  */
 #define AARCH64_HWCAP_PACA (1 << 30)
 
-/* Fetch the AT_HWCAP entry from the auxv vector for the given TARGET.  */
-bool aarch64_linux_get_hwcap (struct target_ops *target, CORE_ADDR *hwcap);
-
 #endif /* AARCH64_LINUX_TDEP_H */
diff --git a/gdb/arm-linux-nat.c b/gdb/arm-linux-nat.c
index 11e353e61c..b54bd5afe9 100644
--- a/gdb/arm-linux-nat.c
+++ b/gdb/arm-linux-nat.c
@@ -533,7 +533,7 @@  ps_get_thread_area (struct ps_prochandle *ph,
 const struct target_desc *
 arm_linux_nat_target::read_description ()
 {
-  CORE_ADDR arm_hwcap = 0;
+  CORE_ADDR arm_hwcap = linux_get_hwcap (this);
 
   if (have_ptrace_getregset == TRIBOOL_UNKNOWN)
     {
@@ -551,11 +551,6 @@  arm_linux_nat_target::read_description ()
 	have_ptrace_getregset = TRIBOOL_TRUE;
     }
 
-  if (target_auxv_search (this, AT_HWCAP, &arm_hwcap) != 1)
-    {
-      return this->beneath ()->read_description ();
-    }
-
   if (arm_hwcap & HWCAP_IWMMXT)
     return tdesc_arm_with_iwmmxt;
 
diff --git a/gdb/arm-linux-tdep.c b/gdb/arm-linux-tdep.c
index 11db9bae32..a5ad06434c 100644
--- a/gdb/arm-linux-tdep.c
+++ b/gdb/arm-linux-tdep.c
@@ -730,10 +730,7 @@  arm_linux_core_read_description (struct gdbarch *gdbarch,
                                  struct target_ops *target,
                                  bfd *abfd)
 {
-  CORE_ADDR arm_hwcap = 0;
-
-  if (target_auxv_search (target, AT_HWCAP, &arm_hwcap) != 1)
-    return NULL;
+  CORE_ADDR arm_hwcap = linux_get_hwcap (target);
 
   if (arm_hwcap & HWCAP_VFP)
     {
diff --git a/gdb/linux-tdep.c b/gdb/linux-tdep.c
index 77bc714286..f6c4f7b208 100644
--- a/gdb/linux-tdep.c
+++ b/gdb/linux-tdep.c
@@ -2462,6 +2462,28 @@  linux_displaced_step_location (struct gdbarch *gdbarch)
   return addr;
 }
 
+/* See linux-tdep.h.  */
+
+CORE_ADDR
+linux_get_hwcap (struct target_ops *target)
+{
+  CORE_ADDR field;
+  if (target_auxv_search (target, AT_HWCAP, &field) != 1)
+    return 0;
+  return field;
+}
+
+/* See linux-tdep.h.  */
+
+CORE_ADDR
+linux_get_hwcap2 (struct target_ops *target)
+{
+  CORE_ADDR field;
+  if (target_auxv_search (target, AT_HWCAP2, &field) != 1)
+    return 0;
+  return field;
+}
+
 /* Display whether the gcore command is using the
    /proc/PID/coredump_filter file.  */
 
diff --git a/gdb/linux-tdep.h b/gdb/linux-tdep.h
index 824ba3afaf..ee9c2bcc90 100644
--- a/gdb/linux-tdep.h
+++ b/gdb/linux-tdep.h
@@ -61,4 +61,10 @@  extern void linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch);
 
 extern int linux_is_uclinux (void);
 
+/* Fetch the AT_HWCAP entry from the auxv vector for the given TARGET.  */
+extern CORE_ADDR linux_get_hwcap (struct target_ops *target);
+
+/* Fetch the AT_HWCAP2 entry from the auxv vector for the given TARGET.  */
+extern CORE_ADDR linux_get_hwcap2 (struct target_ops *target);
+
 #endif /* linux-tdep.h */
diff --git a/gdb/ppc-linux-nat.c b/gdb/ppc-linux-nat.c
index 11394ef36d..3a6bbf4163 100644
--- a/gdb/ppc-linux-nat.c
+++ b/gdb/ppc-linux-nat.c
@@ -1554,31 +1554,6 @@  store_ppc_registers (const struct regcache *regcache, int tid)
      function to fail most of the time, so we ignore them.  */
 }
 
-/* Fetch the AT_HWCAP entry from the aux vector.  */
-static CORE_ADDR
-ppc_linux_get_hwcap (void)
-{
-  CORE_ADDR field;
-
-  if (target_auxv_search (current_top_target (), AT_HWCAP, &field) != 1)
-    return 0;
-
-  return field;
-}
-
-/* Fetch the AT_HWCAP2 entry from the aux vector.  */
-
-static CORE_ADDR
-ppc_linux_get_hwcap2 (void)
-{
-  CORE_ADDR field;
-
-  if (target_auxv_search (current_top_target (), AT_HWCAP2, &field) != 1)
-    return 0;
-
-  return field;
-}
-
 /* The cached DABR value, to install in new threads.
    This variable is used when the PowerPC HWDEBUG ptrace
    interface is not available.  */
@@ -1735,7 +1710,7 @@  ppc_linux_nat_target::region_ok_for_hw_watchpoint (CORE_ADDR addr, int len)
          takes two hardware watchpoints though.  */
       if (len > 1
 	  && hwdebug_info.features & PPC_DEBUG_FEATURE_DATA_BP_RANGE
-	  && ppc_linux_get_hwcap () & PPC_FEATURE_BOOKE)
+	  && linux_get_hwcap (current_top_target ()) & PPC_FEATURE_BOOKE)
 	return 2;
       /* Check if the processor provides DAWR interface.  */
       if (hwdebug_info.features & PPC_DEBUG_FEATURE_DATA_BP_DAWR)
@@ -1755,7 +1730,7 @@  ppc_linux_nat_target::region_ok_for_hw_watchpoint (CORE_ADDR addr, int len)
      ptrace interface, DAC-based processors (i.e., embedded processors) will
      use addresses aligned to 4-bytes due to the way the read/write flags are
      passed in the old ptrace interface.  */
-  else if (((ppc_linux_get_hwcap () & PPC_FEATURE_BOOKE)
+  else if (((linux_get_hwcap (current_top_target ()) & PPC_FEATURE_BOOKE)
 	   && (addr + len) > (addr & ~3) + 4)
 	   || (addr + len) > (addr & ~7) + 8)
     return 0;
@@ -2294,7 +2269,7 @@  ppc_linux_nat_target::insert_watchpoint (CORE_ADDR addr, int len,
       long dabr_value;
       long read_mode, write_mode;
 
-      if (ppc_linux_get_hwcap () & PPC_FEATURE_BOOKE)
+      if (linux_get_hwcap (current_top_target ()) & PPC_FEATURE_BOOKE)
 	{
 	  /* PowerPC 440 requires only the read/write flags to be passed
 	     to the kernel.  */
@@ -2497,9 +2472,9 @@  ppc_linux_nat_target::watchpoint_addr_within_range (CORE_ADDR addr,
   int mask;
 
   if (have_ptrace_hwdebug_interface ()
-      && ppc_linux_get_hwcap () & PPC_FEATURE_BOOKE)
+      && linux_get_hwcap (current_top_target ()) & PPC_FEATURE_BOOKE)
     return start <= addr && start + length >= addr;
-  else if (ppc_linux_get_hwcap () & PPC_FEATURE_BOOKE)
+  else if (linux_get_hwcap (current_top_target ()) & PPC_FEATURE_BOOKE)
     mask = 3;
   else
     mask = 7;
@@ -2637,8 +2612,8 @@  ppc_linux_nat_target::read_description ()
 
   features.wordsize = ppc_linux_target_wordsize (tid);
 
-  CORE_ADDR hwcap = ppc_linux_get_hwcap ();
-  CORE_ADDR hwcap2 = ppc_linux_get_hwcap2 ();
+  CORE_ADDR hwcap = linux_get_hwcap (current_top_target ());
+  CORE_ADDR hwcap2 = linux_get_hwcap2 (current_top_target ());
 
   if (have_ptrace_getsetvsxregs
       && (hwcap & PPC_FEATURE_HAS_VSX))
diff --git a/gdb/ppc-linux-tdep.c b/gdb/ppc-linux-tdep.c
index df44ad826e..19435602b5 100644
--- a/gdb/ppc-linux-tdep.c
+++ b/gdb/ppc-linux-tdep.c
@@ -1601,10 +1601,7 @@  ppc_linux_core_read_description (struct gdbarch *gdbarch,
   if (vsx)
     features.vsx = true;
 
-  CORE_ADDR hwcap;
-
-  if (target_auxv_search (target, AT_HWCAP, &hwcap) != 1)
-    hwcap = 0;
+  CORE_ADDR hwcap = linux_get_hwcap (target);
 
   features.isa205 = ppc_linux_has_isa205 (hwcap);
 
diff --git a/gdb/s390-linux-nat.c b/gdb/s390-linux-nat.c
index 5f6c5be8e0..3a3afae7a6 100644
--- a/gdb/s390-linux-nat.c
+++ b/gdb/s390-linux-nat.c
@@ -1016,9 +1016,8 @@  s390_linux_nat_target::read_description ()
      that mode, report s390 architecture with 64-bit GPRs.  */
 #ifdef __s390x__
   {
-    CORE_ADDR hwcap = 0;
+    CORE_ADDR hwcap = linux_get_hwcap (current_top_target ());
 
-    target_auxv_search (current_top_target (), AT_HWCAP, &hwcap);
     have_regset_tdb = (hwcap & HWCAP_S390_TE)
       && check_regset (tid, NT_S390_TDB, s390_sizeof_tdbregset);
 
diff --git a/gdb/s390-linux-tdep.c b/gdb/s390-linux-tdep.c
index 64fe7abd80..02ae28b4ea 100644
--- a/gdb/s390-linux-tdep.c
+++ b/gdb/s390-linux-tdep.c
@@ -332,10 +332,9 @@  s390_core_read_description (struct gdbarch *gdbarch,
 			    struct target_ops *target, bfd *abfd)
 {
   asection *section = bfd_get_section_by_name (abfd, ".reg");
-  CORE_ADDR hwcap = 0;
+  CORE_ADDR hwcap = linux_get_hwcap (target);
   bool high_gprs, v1, v2, te, vx, gs;
 
-  target_auxv_search (target, AT_HWCAP, &hwcap);
   if (!section)
     return NULL;