linux_dsm_epyc7002/arch/x86/include/asm/ftrace.h
Dmitry Safonov a846446b19 x86/compat: Adjust in_compat_syscall() to generic code under !COMPAT
The result of in_compat_syscall() can be pictured as:

x86 platform:
    ---------------------------------------------------
    |  Arch\syscall  |  64-bit  |   ia32   |   x32    |
    |-------------------------------------------------|
    |     x86_64     |  false   |   true   |   true   |
    |-------------------------------------------------|
    |      i686      |          |  <true>  |          |
    ---------------------------------------------------

Other platforms:
    -------------------------------------------
    |  Arch\syscall  |  64-bit  |   compat    |
    |-----------------------------------------|
    |     64-bit     |  false   |    true     |
    |-----------------------------------------|
    |    32-bit(?)   |          |   <false>   |
    -------------------------------------------

As seen, the result of in_compat_syscall() on generic 32-bit platform
differs from i686.

There is no reason for in_compat_syscall() == true on native i686.  It also
easy to misread code if the result on native 32-bit platform differs
between arches.

Because of that non arch-specific code has many places with:
    if (IS_ENABLED(CONFIG_COMPAT) && in_compat_syscall())
in different variations.

It looks-like the only non-x86 code which uses in_compat_syscall() not
under CONFIG_COMPAT guard is in amd/amdkfd. But according to the commit
a18069c132 ("amdkfd: Disable support for 32-bit user processes"), it
actually should be disabled on native i686.

Rename in_compat_syscall() to in_32bit_syscall() for x86-specific code
and make in_compat_syscall() false under !CONFIG_COMPAT.

A follow on patch will clean up generic users which were forced to check
IS_ENABLED(CONFIG_COMPAT) with in_compat_syscall().

Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-efi@vger.kernel.org
Cc: netdev@vger.kernel.org
Link: https://lkml.kernel.org/r/20181012134253.23266-2-dima@arista.com
2018-11-01 12:59:25 +01:00

86 lines
2.2 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_FTRACE_H
#define _ASM_X86_FTRACE_H
#ifdef CONFIG_FUNCTION_TRACER
#ifdef CC_USING_FENTRY
# define MCOUNT_ADDR ((unsigned long)(__fentry__))
#else
# define MCOUNT_ADDR ((unsigned long)(mcount))
# define HAVE_FUNCTION_GRAPH_FP_TEST
#endif
#define MCOUNT_INSN_SIZE 5 /* sizeof mcount call */
#ifdef CONFIG_DYNAMIC_FTRACE
#define ARCH_SUPPORTS_FTRACE_OPS 1
#endif
#define HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
#ifndef __ASSEMBLY__
extern void mcount(void);
extern atomic_t modifying_ftrace_code;
extern void __fentry__(void);
static inline unsigned long ftrace_call_adjust(unsigned long addr)
{
/*
* addr is the address of the mcount call instruction.
* recordmcount does the necessary offset calculation.
*/
return addr;
}
#ifdef CONFIG_DYNAMIC_FTRACE
struct dyn_arch_ftrace {
/* No extra data needed for x86 */
};
int ftrace_int3_handler(struct pt_regs *regs);
#define FTRACE_GRAPH_TRAMP_ADDR FTRACE_GRAPH_ADDR
#endif /* CONFIG_DYNAMIC_FTRACE */
#endif /* __ASSEMBLY__ */
#endif /* CONFIG_FUNCTION_TRACER */
#ifndef __ASSEMBLY__
#define ARCH_HAS_SYSCALL_MATCH_SYM_NAME
static inline bool arch_syscall_match_sym_name(const char *sym, const char *name)
{
/*
* Compare the symbol name with the system call name. Skip the
* "__x64_sys", "__ia32_sys" or simple "sys" prefix.
*/
return !strcmp(sym + 3, name + 3) ||
(!strncmp(sym, "__x64_", 6) && !strcmp(sym + 9, name + 3)) ||
(!strncmp(sym, "__ia32_", 7) && !strcmp(sym + 10, name + 3));
}
#ifndef COMPILE_OFFSETS
#if defined(CONFIG_FTRACE_SYSCALLS) && defined(CONFIG_IA32_EMULATION)
#include <linux/compat.h>
/*
* Because ia32 syscalls do not map to x86_64 syscall numbers
* this screws up the trace output when tracing a ia32 task.
* Instead of reporting bogus syscalls, just do not trace them.
*
* If the user really wants these, then they should use the
* raw syscall tracepoints with filtering.
*/
#define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS 1
static inline bool arch_trace_is_compat_syscall(struct pt_regs *regs)
{
return in_32bit_syscall();
}
#endif /* CONFIG_FTRACE_SYSCALLS && CONFIG_IA32_EMULATION */
#endif /* !COMPILE_OFFSETS */
#endif /* !__ASSEMBLY__ */
#endif /* _ASM_X86_FTRACE_H */