syscall_get_arch: add "struct task_struct *" argument

This argument is required to extend the generic ptrace API with
PTRACE_GET_SYSCALL_INFO request: syscall_get_arch() is going
to be called from ptrace_request() along with syscall_get_nr(),
syscall_get_arguments(), syscall_get_error(), and
syscall_get_return_value() functions with a tracee as their argument.

The primary intent is that the triple (audit_arch, syscall_nr, arg1..arg6)
should describe what system call is being called and what its arguments
are.

Reverts: 5e937a9ae913 ("syscall_get_arch: remove useless function arguments")
Reverts: 1002d94d3076 ("syscall.h: fix doc text for syscall_get_arch()")
Reviewed-by: Andy Lutomirski <[e-mail]> # for x86
Reviewed-by: Palmer Dabbelt <[e-mail]>
Acked-by: Paul Moore <[e-mail]>
Acked-by: Paul Burton <[e-mail]> # MIPS parts
Acked-by: Michael Ellerman <[e-mail]> (powerpc)
Acked-by: Kees Cook <[e-mail]> # seccomp parts
Acked-by: Mark Salter <[e-mail]> # for the c6x bit
Cc: Elvira Khabirova <[e-mail]>
Cc: Eugene Syromyatnikov <[e-mail]>
Cc: Oleg Nesterov <[e-mail]>
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Signed-off-by: Dmitry V. Levin <[e-mail]>
Signed-off-by: Paul Moore <[e-mail]>

arch/alpha/include/asm/syscall.h

···
 
 #include <uapi/linux/audit.h>
 
-static inline int syscall_get_arch(void)
+static inline int syscall_get_arch(struct task_struct *task)
 {
 	return AUDIT_ARCH_ALPHA;
 }

arch/arc/include/asm/syscall.h

···
 }
 
 static inline int
-syscall_get_arch(void)
+syscall_get_arch(struct task_struct *task)
 {
 	return IS_ENABLED(CONFIG_ISA_ARCOMPACT)
 		? (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN)

arch/arm/include/asm/syscall.h

···
 	memcpy(&regs->ARM_r0 + i, args, n * sizeof(args[0]));
 }
 
-static inline int syscall_get_arch(void)
+static inline int syscall_get_arch(struct task_struct *task)
 {
 	/* ARM tasks don't change audit architectures on the fly. */
 	return AUDIT_ARCH_ARM;

arch/arm64/include/asm/syscall.h

···
  * We don't care about endianness (__AUDIT_ARCH_LE bit) here because
  * AArch64 has the same system calls both on little- and big- endian.
  */
-static inline int syscall_get_arch(void)
+static inline int syscall_get_arch(struct task_struct *task)
 {
-	if (is_compat_task())
+	if (is_compat_thread(task_thread_info(task)))
 		return AUDIT_ARCH_ARM;
 
 	return AUDIT_ARCH_AARCH64;

arch/c6x/include/asm/syscall.h

···
 	}
 }
 
-static inline int syscall_get_arch(void)
+static inline int syscall_get_arch(struct task_struct *task)
 {
 	return IS_ENABLED(CONFIG_CPU_BIG_ENDIAN)
 		? AUDIT_ARCH_C6XBE : AUDIT_ARCH_C6X;

arch/csky/include/asm/syscall.h

···
 }
 
 static inline int
-syscall_get_arch(void)
+syscall_get_arch(struct task_struct *task)
 {
 	return AUDIT_ARCH_CSKY;
 }

arch/h8300/include/asm/syscall.h

···
 }
 
 static inline int
-syscall_get_arch(void)
+syscall_get_arch(struct task_struct *task)
 {
 	return AUDIT_ARCH_H8300;
 }

arch/hexagon/include/asm/syscall.h

···
 	memcpy(args, &(&regs->r00)[i], n * sizeof(args[0]));
 }
 
-static inline int syscall_get_arch(void)
+static inline int syscall_get_arch(struct task_struct *task)
 {
 	return AUDIT_ARCH_HEXAGON;
 }

arch/ia64/include/asm/syscall.h

···
 	ia64_syscall_get_set_arguments(task, regs, i, n, args, 1);
 }
 
-static inline int syscall_get_arch(void)
+static inline int syscall_get_arch(struct task_struct *task)
 {
 	return AUDIT_ARCH_IA64;
 }

arch/m68k/include/asm/syscall.h

···
 
 #include <uapi/linux/audit.h>
 
-static inline int syscall_get_arch(void)
+static inline int syscall_get_arch(struct task_struct *task)
 {
 	return AUDIT_ARCH_M68K;
 }

arch/microblaze/include/asm/syscall.h

···
 asmlinkage unsigned long do_syscall_trace_enter(struct pt_regs *regs);
 asmlinkage void do_syscall_trace_leave(struct pt_regs *regs);
 
-static inline int syscall_get_arch(void)
+static inline int syscall_get_arch(struct task_struct *task)
 {
 	return AUDIT_ARCH_MICROBLAZE;
 }

arch/mips/include/asm/syscall.h

···
 extern const unsigned long sys32_call_table[];
 extern const unsigned long sysn32_call_table[];
 
-static inline int syscall_get_arch(void)
+static inline int syscall_get_arch(struct task_struct *task)
 {
 	int arch = AUDIT_ARCH_MIPS;
 #ifdef CONFIG_64BIT
-	if (!test_thread_flag(TIF_32BIT_REGS)) {
+	if (!test_tsk_thread_flag(task, TIF_32BIT_REGS)) {
 		arch |= __AUDIT_ARCH_64BIT;
 		/* N32 sets only TIF_32BIT_ADDR */
-		if (test_thread_flag(TIF_32BIT_ADDR))
+		if (test_tsk_thread_flag(task, TIF_32BIT_ADDR))
 			arch |= __AUDIT_ARCH_CONVENTION_MIPS64_N32;
 	}
 #endif

arch/mips/kernel/ptrace.c

···
 		unsigned long args[6];
 
 		sd.nr = syscall;
-		sd.arch = syscall_get_arch();
+		sd.arch = syscall_get_arch(current);
 		syscall_get_arguments(current, regs, 0, 6, args);
 		for (i = 0; i < 6; i++)
 			sd.args[i] = args[i];

arch/nds32/include/asm/syscall.h

···
 }
 
 static inline int
-syscall_get_arch(void)
+syscall_get_arch(struct task_struct *task)
 {
 	return IS_ENABLED(CONFIG_CPU_BIG_ENDIAN)
 		? AUDIT_ARCH_NDS32BE : AUDIT_ARCH_NDS32;

arch/nios2/include/asm/syscall.h

···
 	}
 }
 
-static inline int syscall_get_arch(void)
+static inline int syscall_get_arch(struct task_struct *task)
 {
 	return AUDIT_ARCH_NIOS2;
 }

arch/openrisc/include/asm/syscall.h

···
 	memcpy(&regs->gpr[3 + i], args, n * sizeof(args[0]));
 }
 
-static inline int syscall_get_arch(void)
+static inline int syscall_get_arch(struct task_struct *task)
 {
 	return AUDIT_ARCH_OPENRISC;
 }

arch/parisc/include/asm/syscall.h

···
 	/* do nothing */
 }
 
-static inline int syscall_get_arch(void)
+static inline int syscall_get_arch(struct task_struct *task)
 {
 	int arch = AUDIT_ARCH_PARISC;
 #ifdef CONFIG_64BIT
-	if (!is_compat_task())
+	if (!__is_compat_task(task))
 		arch = AUDIT_ARCH_PARISC64;
 #endif
 	return arch;

arch/powerpc/include/asm/syscall.h

···
 		regs->orig_gpr3 = args[0];
 }
 
-static inline int syscall_get_arch(void)
+static inline int syscall_get_arch(struct task_struct *task)
 {
-	int arch = is_32bit_task() ? AUDIT_ARCH_PPC : AUDIT_ARCH_PPC64;
+	int arch;
+
+	if (IS_ENABLED(CONFIG_PPC64) && !test_tsk_thread_flag(task, TIF_32BIT))
+		arch = AUDIT_ARCH_PPC64;
+	else
+		arch = AUDIT_ARCH_PPC;
+
 #ifdef __LITTLE_ENDIAN__
 	arch |= __AUDIT_ARCH_LE;
 #endif

arch/riscv/include/asm/syscall.h

···
 	memcpy(&regs->a1 + i * sizeof(regs->a1), args, n * sizeof(regs->a0));
 }
 
-static inline int syscall_get_arch(void)
+static inline int syscall_get_arch(struct task_struct *task)
 {
 #ifdef CONFIG_64BIT
 	return AUDIT_ARCH_RISCV64;

arch/s390/include/asm/syscall.h

···
 		regs->orig_gpr2 = args[0];
 }
 
-static inline int syscall_get_arch(void)
+static inline int syscall_get_arch(struct task_struct *task)
 {
 #ifdef CONFIG_COMPAT
-	if (test_tsk_thread_flag(current, TIF_31BIT))
+	if (test_tsk_thread_flag(task, TIF_31BIT))
 		return AUDIT_ARCH_S390;
 #endif
 	return AUDIT_ARCH_S390X;

arch/sh/include/asm/syscall_32.h

···
 	}
 }
 
-static inline int syscall_get_arch(void)
+static inline int syscall_get_arch(struct task_struct *task)
 {
 	int arch = AUDIT_ARCH_SH;
 

arch/sh/include/asm/syscall_64.h

···
 	memcpy(&regs->regs[2 + i], args, n * sizeof(args[0]));
 }
 
-static inline int syscall_get_arch(void)
+static inline int syscall_get_arch(struct task_struct *task)
 {
 	int arch = AUDIT_ARCH_SH;
 

arch/sparc/include/asm/syscall.h

···
 		regs->u_regs[UREG_I0 + i + j] = args[j];
 }
 
-static inline int syscall_get_arch(void)
+static inline int syscall_get_arch(struct task_struct *task)
 {
 #if defined(CONFIG_SPARC64) && defined(CONFIG_COMPAT)
-	return in_compat_syscall() ? AUDIT_ARCH_SPARC : AUDIT_ARCH_SPARC64;
+	return test_tsk_thread_flag(task, TIF_32BIT)
+		? AUDIT_ARCH_SPARC : AUDIT_ARCH_SPARC64;
 #elif defined(CONFIG_SPARC64)
 	return AUDIT_ARCH_SPARC64;
 #else

arch/unicore32/include/asm/syscall.h

···
 
 #include <uapi/linux/audit.h>
 
-static inline int syscall_get_arch(void)
+static inline int syscall_get_arch(struct task_struct *task)
 {
 	return AUDIT_ARCH_UNICORE;
 }

arch/x86/include/asm/syscall.h

···
 	memcpy(&regs->bx + i, args, n * sizeof(args[0]));
 }
 
-static inline int syscall_get_arch(void)
+static inline int syscall_get_arch(struct task_struct *task)
 {
 	return AUDIT_ARCH_I386;
 }
···
 		}
 }
 
-static inline int syscall_get_arch(void)
+static inline int syscall_get_arch(struct task_struct *task)
 {
 	/* x32 tasks should be considered AUDIT_ARCH_X86_64. */
-	return in_ia32_syscall() ? AUDIT_ARCH_I386 : AUDIT_ARCH_X86_64;
+	return (IS_ENABLED(CONFIG_IA32_EMULATION) &&
+		task->thread_info.status & TS_COMPAT)
+		? AUDIT_ARCH_I386 : AUDIT_ARCH_X86_64;
 }
 #endif	/* CONFIG_X86_32 */
 

arch/x86/um/asm/syscall.h

···
 					  unsigned long, unsigned long,
 					  unsigned long, unsigned long);
 
-static inline int syscall_get_arch(void)
+static inline int syscall_get_arch(struct task_struct *task)
 {
 #ifdef CONFIG_X86_32
 	return AUDIT_ARCH_I386;

arch/xtensa/include/asm/syscall.h

···
 #include <asm/ptrace.h>
 #include <uapi/linux/audit.h>
 
-static inline int syscall_get_arch(void)
+static inline int syscall_get_arch(struct task_struct *task)
 {
 	return AUDIT_ARCH_XTENSA;
 }

include/asm-generic/syscall.h

···
 
 /**
  * syscall_get_arch - return the AUDIT_ARCH for the current system call
+ * @task:	task of interest, must be blocked
  *
  * Returns the AUDIT_ARCH_* based on the system call convention in use.
  *
- * It's only valid to call this when current is stopped on entry to a system
+ * It's only valid to call this when @task is stopped on entry to a system
  * call, due to %TIF_SYSCALL_TRACE, %TIF_SYSCALL_AUDIT, or %TIF_SECCOMP.
  *
  * Architectures which permit CONFIG_HAVE_ARCH_SECCOMP_FILTER must
  * provide an implementation of this.
  */
-int syscall_get_arch(void);
+int syscall_get_arch(struct task_struct *task);
 #endif	/* _ASM_SYSCALL_H */

kernel/auditsc.c

···
 			return;
 	}
 
-	context->arch	    = syscall_get_arch();
+	context->arch	    = syscall_get_arch(current);
 	context->major      = major;
 	context->argv[0]    = a1;
 	context->argv[1]    = a2;
···
 		return;
 	audit_log_task(ab);
 	audit_log_format(ab, " sig=%ld arch=%x syscall=%ld compat=%d ip=0x%lx code=0x%x",
-			 signr, syscall_get_arch(), syscall,
+			 signr, syscall_get_arch(current), syscall,
 			 in_compat_syscall(), KSTK_EIP(current), code);
 	audit_log_end(ab);
 }

kernel/seccomp.c

···
 	unsigned long args[6];
 
 	sd->nr = syscall_get_nr(task, regs);
-	sd->arch = syscall_get_arch();
+	sd->arch = syscall_get_arch(task);
 	syscall_get_arguments(task, regs, 0, 6, args);
 	sd->args[0] = args[0];
 	sd->args[1] = args[1];
···
 	info->si_code = SYS_SECCOMP;
 	info->si_call_addr = (void __user *)KSTK_EIP(current);
 	info->si_errno = reason;
-	info->si_arch = syscall_get_arch();
+	info->si_arch = syscall_get_arch(current);
 	info->si_syscall = syscall;
 }