From: Luis Machado <luis.machado@linaro.org>
To: gdb-patches@sourceware.org
Subject: [PATCH v6 15/25] AArch64: Implement the memory tagging gdbarch hooks
Date: Mon, 22 Mar 2021 10:21:09 -0300 [thread overview]
Message-ID: <20210322132120.1202230-16-luis.machado@linaro.org> (raw)
In-Reply-To: <20210322132120.1202230-1-luis.machado@linaro.org>
Updates on v6:
- Update to use enum class memtag_type.
- Fix formatting issues.
- Changed gdbarch_memtag_to_string parameters.
- Use a length of 1 to fetch the current granule's tag.
Updates on v4:
- Update function names to be more scoped.
- Use of gdb::optional values.
- Fixed up gdbarch hooks.
Updates on v2:
- Update target methods to contain a tag type parameter.
--
This patch implements the memory tagging gdbarch hooks for AArch64, for
the MTE feature.
gdb/ChangeLog:
YYYY-MM-DD Luis Machado <luis.machado@linaro.org>
* aarch64-linux-tdep.c: Include target.h, arch-utils.h, value.h.
(aarch64_mte_get_atag, aarch64_linux_tagged_address_p)
(aarch64_linux_memtag_mismatch_p, aarch64_linux_set_memtags)
(aarch64_linux_get_memtag, aarch64_linux_memtag_to_string): New
functions.
(aarch64_linux_init_abi): Initialize MTE-related gdbarch hooks.
* arch/aarch64-mte-linux.c (aarch64_mte_make_ltag_bits)
(aarch64_mte_make_ltag, aarch64_linux_set_ltag)
(aarch64_linux_get_ltag): New functions.
* arch/aarch64-mte-linux.h (AARCH64_MTE_LOGICAL_TAG_START_BIT)
(AARCH64_MTE_LOGICAL_MAX_VALUE): Define.
(aarch64_mte_make_ltag_bits, aarch64_mte_make_ltag)
(aarch64_mte_set_ltag, aarch64_mte_get_ltag): New prototypes.
---
gdb/aarch64-linux-tdep.c | 207 +++++++++++++++++++++++++++++++++++
gdb/arch/aarch64-mte-linux.c | 38 +++++++
gdb/arch/aarch64-mte-linux.h | 18 +++
3 files changed, 263 insertions(+)
diff --git a/gdb/aarch64-linux-tdep.c b/gdb/aarch64-linux-tdep.c
index 1c45770a287..29440a8510c 100644
--- a/gdb/aarch64-linux-tdep.c
+++ b/gdb/aarch64-linux-tdep.c
@@ -30,6 +30,7 @@
#include "symtab.h"
#include "tramp-frame.h"
#include "trad-frame.h"
+#include "target.h"
#include "target/target.h"
#include "expop.h"
@@ -47,6 +48,9 @@
#include "arch/aarch64-mte-linux.h"
+#include "arch-utils.h"
+#include "value.h"
+
/* Signal frame handling.
+------------+ ^
@@ -1503,6 +1507,184 @@ aarch64_linux_gcc_target_options (struct gdbarch *gdbarch)
return {};
}
+/* Helper to get the allocation tag from a 64-bit ADDRESS.
+
+ Return the allocation tag if successful and nullopt otherwise. */
+
+static gdb::optional<CORE_ADDR>
+aarch64_mte_get_atag (CORE_ADDR address)
+{
+ gdb::byte_vector tags;
+
+ /* Attempt to fetch the allocation tag. */
+ if (!target_fetch_memtags (address, 1, tags,
+ static_cast<int> (memtag_type::allocation)))
+ return {};
+
+ /* Only one tag should've been returned. Make sure we got exactly that. */
+ if (tags.size () != 1)
+ error (_("Target returned an unexpected number of tags."));
+
+ /* Although our tags are 4 bits in size, they are stored in a
+ byte. */
+ return tags[0];
+}
+
+/* Implement the tagged_address_p gdbarch method. */
+
+static bool
+aarch64_linux_tagged_address_p (struct gdbarch *gdbarch, struct value *address)
+{
+ gdb_assert (address != nullptr);
+
+ CORE_ADDR addr = value_as_address (address);
+
+ /* Remove the top byte for the memory range check. */
+ addr = address_significant (gdbarch, addr);
+
+ /* Check if the page that contains ADDRESS is mapped with PROT_MTE. */
+ if (!linux_address_in_memtag_page (addr))
+ return false;
+
+ /* We have a valid tag in the top byte of the 64-bit address. */
+ return true;
+}
+
+/* Implement the memtag_matches_p gdbarch method. */
+
+static bool
+aarch64_linux_memtag_matches_p (struct gdbarch *gdbarch,
+ struct value *address)
+{
+ gdb_assert (address != nullptr);
+
+ /* Make sure we are dealing with a tagged address to begin with. */
+ if (!aarch64_linux_tagged_address_p (gdbarch, address))
+ return true;
+
+ CORE_ADDR addr = value_as_address (address);
+
+ /* Fetch the allocation tag for ADDRESS. */
+ gdb::optional<CORE_ADDR> atag = aarch64_mte_get_atag (addr);
+
+ if (!atag.has_value ())
+ return true;
+
+ /* Fetch the logical tag for ADDRESS. */
+ gdb_byte ltag = aarch64_mte_get_ltag (addr);
+
+ /* Are the tags the same? */
+ return ltag == *atag;
+}
+
+/* Implement the set_memtags gdbarch method. */
+
+static bool
+aarch64_linux_set_memtags (struct gdbarch *gdbarch, struct value *address,
+ size_t length, const gdb::byte_vector &tags,
+ memtag_type tag_type)
+{
+ if (tags.empty ())
+ return true;
+
+ gdb_assert (address != nullptr);
+
+ CORE_ADDR addr = value_as_address (address);
+
+ /* Set the logical tag or the allocation tag. */
+ if (tag_type == memtag_type::logical)
+ {
+ /* When setting logical tags, we don't care about the length, since
+ we are only setting a single logical tag. */
+ addr = aarch64_mte_set_ltag (addr, tags[0]);
+
+ /* Update the value's content with the tag. */
+ enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+ gdb_byte *srcbuf = value_contents_raw (address);
+ store_unsigned_integer (srcbuf, sizeof (addr), byte_order, addr);
+ }
+ else
+ {
+ /* Make sure we are dealing with a tagged address to begin with. */
+ if (!aarch64_linux_tagged_address_p (gdbarch, address))
+ return false;
+
+ /* With G being the number of tag granules and N the number of tags
+ passed in, we can have the following cases:
+
+ 1 - G == N: Store all the N tags to memory.
+
+ 2 - G < N : Warn about having more tags than granules, but write G
+ tags.
+
+ 3 - G > N : This is a "fill tags" operation. We should use the tags
+ as a pattern to fill the granules repeatedly until we have
+ written G tags to memory.
+ */
+
+ size_t g = aarch64_mte_get_tag_granules (addr, length,
+ AARCH64_MTE_GRANULE_SIZE);
+ size_t n = tags.size ();
+
+ if (g < n)
+ warning (_("Got more tags than memory granules. Tags will be "
+ "truncated."));
+ else if (g > n)
+ warning (_("Using tag pattern to fill memory range."));
+
+ if (!target_store_memtags (addr, length, tags,
+ static_cast<int> (memtag_type::allocation)))
+ return false;
+ }
+ return true;
+}
+
+/* Implement the get_memtag gdbarch method. */
+
+static struct value *
+aarch64_linux_get_memtag (struct gdbarch *gdbarch, struct value *address,
+ memtag_type tag_type)
+{
+ gdb_assert (address != nullptr);
+
+ CORE_ADDR addr = value_as_address (address);
+ CORE_ADDR tag = 0;
+
+ /* Get the logical tag or the allocation tag. */
+ if (tag_type == memtag_type::logical)
+ tag = aarch64_mte_get_ltag (addr);
+ else
+ {
+ /* Make sure we are dealing with a tagged address to begin with. */
+ if (!aarch64_linux_tagged_address_p (gdbarch, address))
+ return nullptr;
+
+ gdb::optional<CORE_ADDR> atag = aarch64_mte_get_atag (addr);
+
+ if (!atag.has_value ())
+ return nullptr;
+
+ tag = *atag;
+ }
+
+ /* Convert the tag to a value. */
+ return value_from_ulongest (builtin_type (gdbarch)->builtin_unsigned_int,
+ tag);
+}
+
+/* Implement the memtag_to_string gdbarch method. */
+
+static std::string
+aarch64_linux_memtag_to_string (struct gdbarch *gdbarch, struct value *tag_value)
+{
+ if (tag_value == nullptr)
+ return "";
+
+ CORE_ADDR tag = value_as_address (tag_value);
+
+ return string_printf ("0x%s", phex_nz (tag, sizeof (tag)));
+}
+
static void
aarch64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
@@ -1560,6 +1742,31 @@ aarch64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
data associated with the address. */
set_gdbarch_significant_addr_bit (gdbarch, 56);
+ /* MTE-specific settings and hooks. */
+ if (tdep->has_mte ())
+ {
+ /* Register a hook for checking if an address is tagged or not. */
+ set_gdbarch_tagged_address_p (gdbarch, aarch64_linux_tagged_address_p);
+
+ /* Register a hook for checking if there is a memory tag match. */
+ set_gdbarch_memtag_matches_p (gdbarch,
+ aarch64_linux_memtag_matches_p);
+
+ /* Register a hook for setting the logical/allocation tags for
+ a range of addresses. */
+ set_gdbarch_set_memtags (gdbarch, aarch64_linux_set_memtags);
+
+ /* Register a hook for extracting the logical/allocation tag from an
+ address. */
+ set_gdbarch_get_memtag (gdbarch, aarch64_linux_get_memtag);
+
+ /* Set the allocation tag granule size to 16 bytes. */
+ set_gdbarch_memtag_granule_size (gdbarch, AARCH64_MTE_GRANULE_SIZE);
+
+ /* Register a hook for converting a memory tag to a string. */
+ set_gdbarch_memtag_to_string (gdbarch, aarch64_linux_memtag_to_string);
+ }
+
/* Initialize the aarch64_linux_record_tdep. */
/* These values are the size of the type that will be used in a system
call. They are obtained from Linux Kernel source. */
diff --git a/gdb/arch/aarch64-mte-linux.c b/gdb/arch/aarch64-mte-linux.c
index 3d72b8db308..959c0247ed5 100644
--- a/gdb/arch/aarch64-mte-linux.c
+++ b/gdb/arch/aarch64-mte-linux.c
@@ -36,3 +36,41 @@ aarch64_mte_get_tag_granules (CORE_ADDR addr, size_t len, size_t granule_size)
/* We always have at least 1 granule. */
return 1 + (e_addr - s_addr) / granule_size;
}
+
+/* See arch/aarch64-mte-linux.h */
+
+CORE_ADDR
+aarch64_mte_make_ltag_bits (CORE_ADDR value)
+{
+ return value & AARCH64_MTE_LOGICAL_MAX_VALUE;
+}
+
+/* See arch/aarch64-mte-linux.h */
+
+CORE_ADDR
+aarch64_mte_make_ltag (CORE_ADDR value)
+{
+ return (aarch64_mte_make_ltag_bits (value)
+ << AARCH64_MTE_LOGICAL_TAG_START_BIT);
+}
+
+/* See arch/aarch64-mte-linux.h */
+
+CORE_ADDR
+aarch64_mte_set_ltag (CORE_ADDR address, CORE_ADDR tag)
+{
+ /* Remove the existing tag. */
+ address &= ~aarch64_mte_make_ltag (AARCH64_MTE_LOGICAL_MAX_VALUE);
+
+ /* Return the new tagged address. */
+ return address | aarch64_mte_make_ltag (tag);
+}
+
+/* See arch/aarch64-mte-linux.h */
+
+CORE_ADDR
+aarch64_mte_get_ltag (CORE_ADDR address)
+{
+ CORE_ADDR ltag_addr = address >> AARCH64_MTE_LOGICAL_TAG_START_BIT;
+ return aarch64_mte_make_ltag_bits (ltag_addr);
+}
diff --git a/gdb/arch/aarch64-mte-linux.h b/gdb/arch/aarch64-mte-linux.h
index 88bd8d03cfb..f517638831c 100644
--- a/gdb/arch/aarch64-mte-linux.h
+++ b/gdb/arch/aarch64-mte-linux.h
@@ -32,6 +32,8 @@
/* We have one tag per 16 bytes of memory. */
#define AARCH64_MTE_GRANULE_SIZE 16
+#define AARCH64_MTE_LOGICAL_TAG_START_BIT 56
+#define AARCH64_MTE_LOGICAL_MAX_VALUE 0xf
/* Memory tag types for AArch64. */
enum class aarch64_memtag_type
@@ -47,4 +49,20 @@ enum class aarch64_memtag_type
extern size_t aarch64_mte_get_tag_granules (CORE_ADDR addr, size_t len,
size_t granule_size);
+/* Return the 4-bit tag made from VALUE. */
+extern CORE_ADDR aarch64_mte_make_ltag_bits (CORE_ADDR value);
+
+/* Return the 4-bit tag that can be OR-ed to an address. */
+extern CORE_ADDR aarch64_mte_make_ltag (CORE_ADDR value);
+
+/* Helper to set the logical TAG for a 64-bit ADDRESS.
+
+ It is always possible to set the logical tag. */
+extern CORE_ADDR aarch64_mte_set_ltag (CORE_ADDR address, CORE_ADDR tag);
+
+/* Helper to get the logical tag from a 64-bit ADDRESS.
+
+ It is always possible to get the logical tag. */
+extern CORE_ADDR aarch64_mte_get_ltag (CORE_ADDR address);
+
#endif /* ARCH_AARCH64_LINUX_H */
--
2.25.1
next prev parent reply other threads:[~2021-03-22 13:21 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-22 13:20 [PATCH v6 00/25] Memory Tagging Support + AArch64 Linux implementation Luis Machado
2021-03-22 13:20 ` [PATCH v6 01/25] New target methods for memory tagging support Luis Machado
2021-03-23 21:22 ` Simon Marchi
2021-03-22 13:20 ` [PATCH v6 02/25] New gdbarch memory tagging hooks Luis Machado
2021-03-22 13:20 ` [PATCH v6 03/25] Add GDB-side remote target support for memory tagging Luis Machado
2021-03-22 13:20 ` [PATCH v6 04/25] Unit testing for GDB-side remote memory tagging handling Luis Machado
2021-03-22 13:20 ` [PATCH v6 05/25] GDBserver remote packet support for memory tagging Luis Machado
2021-03-22 13:21 ` [PATCH v6 06/25] Unit tests for gdbserver memory tagging remote packets Luis Machado
2021-03-22 13:21 ` [PATCH v6 07/25] Documentation for " Luis Machado
2021-03-22 17:47 ` Eli Zaretskii
2021-03-22 13:21 ` [PATCH v6 08/25] AArch64: Add MTE CPU feature check support Luis Machado
2021-03-22 13:21 ` [PATCH v6 09/25] AArch64: Add target description/feature for MTE registers Luis Machado
2021-03-22 13:21 ` [PATCH v6 10/25] AArch64: Add MTE register set support for GDB and gdbserver Luis Machado
2021-03-22 13:21 ` [PATCH v6 11/25] AArch64: Add MTE ptrace requests Luis Machado
2021-03-22 13:21 ` [PATCH v6 12/25] AArch64: Implement memory tagging target methods for AArch64 Luis Machado
2021-03-22 13:21 ` [PATCH v6 13/25] Convert char array to std::string in linux_find_memory_regions_full Luis Machado
2021-03-22 13:21 ` [PATCH v6 14/25] Refactor parsing of /proc/<pid>/smaps Luis Machado
2021-03-23 21:28 ` Simon Marchi
2021-03-22 13:21 ` Luis Machado [this message]
2021-03-23 21:32 ` [PATCH v6 15/25] AArch64: Implement the memory tagging gdbarch hooks Simon Marchi
2021-03-22 13:21 ` [PATCH v6 16/25] AArch64: Add unit testing for logical tag set/get operations Luis Machado
2022-01-31 14:34 ` Simon Marchi
2021-03-22 13:21 ` [PATCH v6 17/25] AArch64: Report tag violation error information Luis Machado
2021-03-22 13:21 ` [PATCH v6 18/25] AArch64: Add gdbserver MTE support Luis Machado
2021-03-22 13:21 ` [PATCH v6 19/25] AArch64: Add MTE register set support for core files Luis Machado
2021-03-22 13:21 ` [PATCH v6 20/25] New memory-tag commands Luis Machado
2021-03-22 13:21 ` [PATCH v6 21/25] Documentation for the new mtag commands Luis Machado
2021-03-22 17:49 ` Eli Zaretskii
2021-03-22 13:21 ` [PATCH v6 22/25] Extend "x" and "print" commands to support memory tagging Luis Machado
2021-03-22 13:21 ` [PATCH v6 23/25] Document new "x" and "print" memory tagging extensions Luis Machado
2021-03-22 17:51 ` Eli Zaretskii
2021-03-22 13:21 ` [PATCH v6 24/25] Add NEWS entry Luis Machado
2021-03-22 17:51 ` Eli Zaretskii
2021-03-22 17:52 ` Luis Machado
2021-03-22 13:21 ` [PATCH v6 25/25] Add memory tagging testcases Luis Machado
2021-03-23 22:50 ` [PATCH v6 00/25] Memory Tagging Support + AArch64 Linux implementation Simon Marchi
2021-03-24 18:18 ` Luis Machado
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