linux/arch/x86/include/asm/sigframe.h
Chang S. Bae 939ef71329 x86/signal: Introduce helpers to get the maximum signal frame size
Signal frames do not have a fixed format and can vary in size when a number
of things change: supported XSAVE features, 32 vs. 64-bit apps, etc.

Add support for a runtime method for userspace to dynamically discover
how large a signal stack needs to be.

Introduce a new variable, max_frame_size, and helper functions for the
calculation to be used in a new user interface. Set max_frame_size to a
system-wide worst-case value, instead of storing multiple app-specific
values.

Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Len Brown <len.brown@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: H.J. Lu <hjl.tools@gmail.com>
Link: https://lkml.kernel.org/r/20210518200320.17239-3-chang.seok.bae@intel.com
2021-05-19 11:46:27 +02:00

91 lines
2.1 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_SIGFRAME_H
#define _ASM_X86_SIGFRAME_H
#include <uapi/asm/sigcontext.h>
#include <asm/siginfo.h>
#include <asm/ucontext.h>
#include <linux/compat.h>
#ifdef CONFIG_X86_32
#define sigframe_ia32 sigframe
#define rt_sigframe_ia32 rt_sigframe
#define ucontext_ia32 ucontext
#else /* !CONFIG_X86_32 */
#ifdef CONFIG_IA32_EMULATION
#include <asm/ia32.h>
#endif /* CONFIG_IA32_EMULATION */
#endif /* CONFIG_X86_32 */
#if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)
struct sigframe_ia32 {
u32 pretcode;
int sig;
struct sigcontext_32 sc;
/*
* fpstate is unused. fpstate is moved/allocated after
* retcode[] below. This movement allows to have the FP state and the
* future state extensions (xsave) stay together.
* And at the same time retaining the unused fpstate, prevents changing
* the offset of extramask[] in the sigframe and thus prevent any
* legacy application accessing/modifying it.
*/
struct _fpstate_32 fpstate_unused;
unsigned int extramask[1];
char retcode[8];
/* fp state follows here */
};
struct rt_sigframe_ia32 {
u32 pretcode;
int sig;
u32 pinfo;
u32 puc;
#ifdef CONFIG_IA32_EMULATION
compat_siginfo_t info;
#else /* !CONFIG_IA32_EMULATION */
struct siginfo info;
#endif /* CONFIG_IA32_EMULATION */
struct ucontext_ia32 uc;
char retcode[8];
/* fp state follows here */
};
#endif /* defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION) */
#ifdef CONFIG_X86_64
struct rt_sigframe {
char __user *pretcode;
struct ucontext uc;
struct siginfo info;
/* fp state follows here */
};
#ifdef CONFIG_X86_X32_ABI
struct ucontext_x32 {
unsigned int uc_flags;
unsigned int uc_link;
compat_stack_t uc_stack;
unsigned int uc__pad0; /* needed for alignment */
struct sigcontext uc_mcontext; /* the 64-bit sigcontext type */
compat_sigset_t uc_sigmask; /* mask last for extensibility */
};
struct rt_sigframe_x32 {
u64 pretcode;
struct ucontext_x32 uc;
compat_siginfo_t info;
/* fp state follows here */
};
#endif /* CONFIG_X86_X32_ABI */
#endif /* CONFIG_X86_64 */
void __init init_sigframe_size(void);
#endif /* _ASM_X86_SIGFRAME_H */