/* GNU/Linux/x86-64 specific low level interface, for the in-process
agent library for GDB.
- Copyright (C) 2010-2016 Free Software Foundation, Inc.
+ Copyright (C) 2010-2018 Free Software Foundation, Inc.
This file is part of GDB.
#include <sys/mman.h>
#include "tracepoint.h"
#include "linux-x86-tdesc.h"
+#include "common/x86-xstate.h"
/* Defined in auto-generated file amd64-linux.c. */
void init_registers_amd64_linux (void);
#endif /* HAVE_UST */
+#if !defined __ILP32__
+/* Map the tdesc index to xcr0 mask. */
+static uint64_t idx2mask[X86_TDESC_LAST] = {
+ X86_XSTATE_X87_MASK,
+ X86_XSTATE_SSE_MASK,
+ X86_XSTATE_AVX_MASK,
+ X86_XSTATE_MPX_MASK,
+ X86_XSTATE_AVX_MPX_MASK,
+ X86_XSTATE_AVX_AVX512_MASK,
+ X86_XSTATE_AVX_MPX_AVX512_PKU_MASK,
+};
+#endif
+
/* Return target_desc to use for IPA, given the tdesc index passed by
gdbserver. */
const struct target_desc *
get_ipa_tdesc (int idx)
{
+ if (idx >= X86_TDESC_LAST)
+ {
+ internal_error (__FILE__, __LINE__,
+ "unknown ipa tdesc index: %d", idx);
+ }
+
+#if defined __ILP32__
switch (idx)
{
case X86_TDESC_SSE:
- return tdesc_amd64_linux;
+ return amd64_linux_read_description (X86_XSTATE_SSE_MASK, true);
case X86_TDESC_AVX:
- return tdesc_amd64_avx_linux;
- case X86_TDESC_MPX:
- return tdesc_amd64_mpx_linux;
- case X86_TDESC_AVX512:
- return tdesc_amd64_avx512_linux;
+ return amd64_linux_read_description (X86_XSTATE_AVX_MASK, true);
+ case X86_TDESC_AVX_AVX512:
+ return amd64_linux_read_description (X86_XSTATE_AVX_AVX512_MASK, true);
default:
- internal_error (__FILE__, __LINE__,
- "unknown ipa tdesc index: %d", idx);
- return tdesc_amd64_linux;
+ break;
}
+#else
+ return amd64_linux_read_description (idx2mask[idx], false);
+#endif
+
+ internal_error (__FILE__, __LINE__,
+ "unknown ipa tdesc index: %d", idx);
}
-/* Allocate buffer for the jump pads. Since we're using 32-bit jumps
- to reach them, and the executable is at low addresses, MAP_32BIT
- works just fine. Shared libraries, being allocated at the top,
- are unfortunately out of luck. */
+/* Allocate buffer for the jump pads. The branch instruction has a
+ reach of +/- 31-bit, and the executable is loaded at low addresses.
+
+ 64-bit: Use MAP_32BIT to allocate in the first 2GB. Shared
+ libraries, being allocated at the top, are unfortunately out of
+ luck.
+
+ x32: Since MAP_32BIT is 64-bit only, do the placement manually.
+ Try allocating at '0x80000000 - SIZE' initially, decreasing until
+ we hit a free area. This ensures the executable is fully covered,
+ and is as close as possible to the shared libraries, which are
+ usually mapped at the top of the first 4GB of the address space.
+*/
void *
alloc_jump_pad_buffer (size_t size)
{
+#if __ILP32__
+ uintptr_t addr;
+ int pagesize;
+
+ pagesize = sysconf (_SC_PAGE_SIZE);
+ if (pagesize == -1)
+ perror_with_name ("sysconf");
+
+ addr = 0x80000000 - size;
+
+ /* size should already be page-aligned, but this can't hurt. */
+ addr &= ~(pagesize - 1);
+
+ /* Search for a free area. If we hit 0, we're out of luck. */
+ for (; addr; addr -= pagesize)
+ {
+ void *res;
+
+ /* No MAP_FIXED - we don't want to zap someone's mapping. */
+ res = mmap ((void *) addr, size,
+ PROT_READ | PROT_WRITE | PROT_EXEC,
+ MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+
+ /* If we got what we wanted, return. */
+ if ((uintptr_t) res == addr)
+ return res;
+
+ /* If we got a mapping, but at a wrong address, undo it. */
+ if (res != MAP_FAILED)
+ munmap (res, size);
+ }
+
+ return NULL;
+#else
void *res = mmap (NULL, size, PROT_READ | PROT_WRITE | PROT_EXEC,
MAP_PRIVATE | MAP_ANONYMOUS | MAP_32BIT, -1, 0);
return NULL;
return res;
+#endif
}
void
initialize_low_tracepoint (void)
{
- init_registers_amd64_linux ();
- init_registers_amd64_avx_linux ();
- init_registers_amd64_mpx_linux ();
- init_registers_amd64_avx512_linux ();
+#if defined __ILP32__
+ amd64_linux_read_description (X86_XSTATE_SSE_MASK, true);
+ amd64_linux_read_description (X86_XSTATE_AVX_MASK, true);
+ amd64_linux_read_description (X86_XSTATE_AVX_AVX512_MASK, true);
+#else
+ for (auto i = 0; i < X86_TDESC_LAST; i++)
+ amd64_linux_read_description (idx2mask[i], false);
+#endif
}