[PATCH v3 1/1] arm64: remove unnecessary ifdefs around is_compat_task()
Leonardo Bras
leobras at redhat.com
Mon Jan 8 19:46:50 PST 2024
Currently some parts of the codebase will test for CONFIG_COMPAT before
testing is_compat_task().
is_compat_task() is a inlined function only present on CONFIG_COMPAT.
On the other hand, for !CONFIG_COMPAT, we have in linux/compat.h:
#define is_compat_task() (0)
Since we have this define available in every usage of is_compat_task() for
!CONFIG_COMPAT, it's unnecessary to keep the ifdefs, since the compiler is
smart enough to optimize-out those snippets on CONFIG_COMPAT=n
This requires some regset code as well as a few other defines to be made
available on !CONFIG_COMPAT, so some symbols can get resolved before
getting optimized-out.
Signed-off-by: Leonardo Bras <leobras at redhat.com>
Reviewed-by: Arnd Bergmann <arnd at arndb.de>
---
Changes since v2:
- Added Reviewd-by from Arnd
Link: https://lore.kernel.org/all/20240108174330.472996-2-leobras@redhat.com/
Changes since v1:
- Move some regset code and other defines outside of CONFIG_COMPAT
- Closes: https://lore.kernel.org/oe-kbuild-all/202401061219.Y2LD7LTx-lkp@intel.com/
Link: https://lore.kernel.org/all/20240105041458.126602-3-leobras@redhat.com/
Changes since RFCv1:
- Removed unnecessary new inlined is_compat_task() for arm64
- Adjusted commit text and title
Link: https://lore.kernel.org/all/20240104192433.109983-2-leobras@redhat.com/
arch/arm64/include/asm/elf.h | 10 +++++-----
arch/arm64/include/asm/fpsimd.h | 2 --
arch/arm64/kernel/ptrace.c | 8 +++-----
arch/arm64/kernel/syscall.c | 5 +----
4 files changed, 9 insertions(+), 16 deletions(-)
diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h
index 97932fbf973d1..3f93f4eef9530 100644
--- a/arch/arm64/include/asm/elf.h
+++ b/arch/arm64/include/asm/elf.h
@@ -201,16 +201,16 @@ extern int arch_setup_additional_pages(struct linux_binprm *bprm,
#define COMPAT_ELF_PLATFORM ("v8l")
#endif
-#ifdef CONFIG_COMPAT
-
-/* PIE load location for compat arm. Must match ARM ELF_ET_DYN_BASE. */
-#define COMPAT_ELF_ET_DYN_BASE 0x000400000UL
-
/* AArch32 registers. */
#define COMPAT_ELF_NGREG 18
typedef unsigned int compat_elf_greg_t;
typedef compat_elf_greg_t compat_elf_gregset_t[COMPAT_ELF_NGREG];
+#ifdef CONFIG_COMPAT
+
+/* PIE load location for compat arm. Must match ARM ELF_ET_DYN_BASE. */
+#define COMPAT_ELF_ET_DYN_BASE 0x000400000UL
+
/* AArch32 EABI. */
#define EF_ARM_EABI_MASK 0xff000000
int compat_elf_check_arch(const struct elf32_hdr *);
diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h
index 50e5f25d3024c..94c7ed82fbada 100644
--- a/arch/arm64/include/asm/fpsimd.h
+++ b/arch/arm64/include/asm/fpsimd.h
@@ -21,7 +21,6 @@
#include <linux/stddef.h>
#include <linux/types.h>
-#ifdef CONFIG_COMPAT
/* Masks for extracting the FPSR and FPCR from the FPSCR */
#define VFP_FPSCR_STAT_MASK 0xf800009f
#define VFP_FPSCR_CTRL_MASK 0x07f79f00
@@ -30,7 +29,6 @@
* control/status register.
*/
#define VFP_STATE_SIZE ((32 * 8) + 4)
-#endif
static inline unsigned long cpacr_save_enable_kernel_sve(void)
{
diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index 20d7ef82de90a..27efd66fc1e93 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -173,7 +173,6 @@ static void ptrace_hbptriggered(struct perf_event *bp,
struct arch_hw_breakpoint *bkpt = counter_arch_bp(bp);
const char *desc = "Hardware breakpoint trap (ptrace)";
-#ifdef CONFIG_COMPAT
if (is_compat_task()) {
int si_errno = 0;
int i;
@@ -195,7 +194,7 @@ static void ptrace_hbptriggered(struct perf_event *bp,
desc);
return;
}
-#endif
+
arm64_force_sig_fault(SIGTRAP, TRAP_HWBKPT, bkpt->trigger, desc);
}
@@ -1594,7 +1593,6 @@ static const struct user_regset_view user_aarch64_view = {
.regsets = aarch64_regsets, .n = ARRAY_SIZE(aarch64_regsets)
};
-#ifdef CONFIG_COMPAT
enum compat_regset {
REGSET_COMPAT_GPR,
REGSET_COMPAT_VFP,
@@ -1851,6 +1849,7 @@ static const struct user_regset_view user_aarch32_ptrace_view = {
.regsets = aarch32_ptrace_regsets, .n = ARRAY_SIZE(aarch32_ptrace_regsets)
};
+#ifdef CONFIG_COMPAT
static int compat_ptrace_read_user(struct task_struct *tsk, compat_ulong_t off,
compat_ulong_t __user *ret)
{
@@ -2112,7 +2111,6 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
const struct user_regset_view *task_user_regset_view(struct task_struct *task)
{
-#ifdef CONFIG_COMPAT
/*
* Core dumping of 32-bit tasks or compat ptrace requests must use the
* user_aarch32_view compatible with arm32. Native ptrace requests on
@@ -2123,7 +2121,7 @@ const struct user_regset_view *task_user_regset_view(struct task_struct *task)
return &user_aarch32_view;
else if (is_compat_thread(task_thread_info(task)))
return &user_aarch32_ptrace_view;
-#endif
+
return &user_aarch64_view;
}
diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c
index 9a70d9746b661..ad198262b9817 100644
--- a/arch/arm64/kernel/syscall.c
+++ b/arch/arm64/kernel/syscall.c
@@ -20,14 +20,11 @@ long sys_ni_syscall(void);
static long do_ni_syscall(struct pt_regs *regs, int scno)
{
-#ifdef CONFIG_COMPAT
- long ret;
if (is_compat_task()) {
- ret = compat_arm_syscall(regs, scno);
+ long ret = compat_arm_syscall(regs, scno);
if (ret != -ENOSYS)
return ret;
}
-#endif
return sys_ni_syscall();
}
--
2.43.0
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