posix-timers: Get rid of [COMPAT_]SYS_NI() uses

Only the posix timer system calls use this (when the posix timer support
is disabled, which does not actually happen in any normal case), because
they

posix-timers: Get rid of [COMPAT_]SYS_NI() uses

Only the posix timer system calls use this (when the posix timer support
is disabled, which does not actually happen in any normal case), because
they had debug code to print out a warning about missing system calls.

Get rid of that special case, and just use the standard COND_SYSCALL
interface that creates weak system call stubs that return -ENOSYS for
when the system call does not exist.

This fixes a kCFI issue with the SYS_NI() hackery:

CFI failure at int80_emulation+0x67/0xb0 (target: sys_ni_posix_timers+0x0/0x70; expected type: 0xb02b34d9)
WARNING: CPU: 0 PID: 48 at int80_emulation+0x67/0xb0

Reported-by: kernel test robot <[email protected]>
Reviewed-by: Sami Tolvanen <[email protected]>
Tested-by: Sami Tolvanen <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Borislav Petkov <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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arm64/syscall: Remove duplicate declaration

Commit 6ac19f96515e ("arm64: avoid prototype warnings for syscalls")
added missing declarations to various syscall wrapper macros. It
however proved a lit

arm64/syscall: Remove duplicate declaration

Commit 6ac19f96515e ("arm64: avoid prototype warnings for syscalls")
added missing declarations to various syscall wrapper macros. It
however proved a little too zealous in __SYSCALL_DEFINEx(), as a
declaration for __arm64_sys##name was already present. A declaration
is required before the call to ALLOW_ERROR_INJECTION(), so keep
the original one and remove the new one.

Fixes: 6ac19f96515e ("arm64: avoid prototype warnings for syscalls")
Signed-off-by: Kevin Brodsky <[email protected]>
Acked-by: Arnd Bergmann <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Catalin Marinas <[email protected]>

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arm64: avoid prototype warnings for syscalls

With W=1 warnings enabled, there are lots of complaints about
missing prototypes for system calls, plus a few other related
ones:

arch/arm64/kernel/sys_

arm64: avoid prototype warnings for syscalls

With W=1 warnings enabled, there are lots of complaints about
missing prototypes for system calls, plus a few other related
ones:

arch/arm64/kernel/sys_compat.c:68:6: error: no previous prototype for 'compat_arm_syscall' [-Werror=missing-prototypes]
arch/arm64/include/asm/syscall_wrapper.h:76:32: error: no previous prototype for '__arm64_sys_io_setup' [-Werror=missing-prototypes]
arch/arm64/include/asm/syscall_wrapper.h:41:32: error: no previous prototype for '__arm64_compat_sys_io_setup' [-Werror=missing-prototypes]
arch/arm64/include/asm/syscall_wrapper.h:76:32: error: no previous prototype for '__arm64_sys_io_destroy' [-Werror=missing-prototypes]
arch/arm64/include/asm/syscall_wrapper.h:76:32: error: no previous prototype for '__arm64_sys_io_submit' [-Werror=missing-prototypes]

Add declarations to the syscall macros to avoid all of these, plus
one for the compat syscall entry.

Signed-off-by: Arnd Bergmann <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Acked-by: Ard Biesheuvel <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Catalin Marinas <[email protected]>

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arm64/syscall: Include asm/ptrace.h in syscall_wrapper header.

Add the same change for ARM64 as done in the commit 9440c4294160
("x86/syscall: Include asm/ptrace.h in syscall_wrapper header") to
mak

arm64/syscall: Include asm/ptrace.h in syscall_wrapper header.

Add the same change for ARM64 as done in the commit 9440c4294160
("x86/syscall: Include asm/ptrace.h in syscall_wrapper header") to
make sure all syscalls see 'struct pt_regs' definition and resulted
BTF for '__arm64_sys_*(struct pt_regs *regs)' functions point to
actual struct.

Without this patch, the BPF verifier refuses to load a tracing prog
which accesses pt_regs.

bpf(BPF_PROG_LOAD, {prog_type=0x1a, ...}, 128) = -1 EACCES

With this patch, we can see the correct error, which saves us time
in debugging the prog.

bpf(BPF_PROG_LOAD, {prog_type=0x1a, ...}, 128) = 4
bpf(BPF_RAW_TRACEPOINT_OPEN, {raw_tracepoint={name=NULL, prog_fd=4}}, 128) = -1 ENOTSUPP

Signed-off-by: Kuniyuki Iwashima <[email protected]>
Acked-by: Andrii Nakryiko <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Catalin Marinas <[email protected]>

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arm64: simplify syscall wrapper ifdeffery

Back in commit:

4378a7d4be30ec69 ("arm64: implement syscall wrappers")

... I implemented the arm64 syscall wrapper glue following the approach
taken on

arm64: simplify syscall wrapper ifdeffery

Back in commit:

4378a7d4be30ec69 ("arm64: implement syscall wrappers")

... I implemented the arm64 syscall wrapper glue following the approach
taken on x86. While doing so, I also copied across some ifdeffery that
isn't necessary on arm64.

On arm64 we don't share any of the native wrappers with compat tasks,
and unlike x86 we don't have alternative implementations of
SYSCALL_DEFINE0(), COND_SYSCALL(), or SYS_NI() defined when AArch32
compat support is enabled.

Thus we don't need to prevent multiple definitions of these macros, and
can remove the #ifndef ... #endif guards protecting them. If any of
these had been previously defined elsewhere, syscalls are unlikely to
work correctly, and we'd want the compiler to warn about the multiple
definitions.

Acked-by: Will Deacon <[email protected]>
Signed-off-by: Mark Rutland <[email protected]>
Signed-off-by: Catalin Marinas <[email protected]>

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arm64: fix function types in COND_SYSCALL

Define a weak function in COND_SYSCALL instead of a weak alias to
sys_ni_syscall, which has an incompatible type. This fixes indirect
call mismatches with C

arm64: fix function types in COND_SYSCALL

Define a weak function in COND_SYSCALL instead of a weak alias to
sys_ni_syscall, which has an incompatible type. This fixes indirect
call mismatches with Control-Flow Integrity (CFI) checking.

Acked-by: Mark Rutland <[email protected]>
Signed-off-by: Sami Tolvanen <[email protected]>
Signed-off-by: Will Deacon <[email protected]>

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arm64: use the correct function type in SYSCALL_DEFINE0

Although a syscall defined using SYSCALL_DEFINE0 doesn't accept
parameters, use the correct function type to avoid indirect call
type mismatch

arm64: use the correct function type in SYSCALL_DEFINE0

Although a syscall defined using SYSCALL_DEFINE0 doesn't accept
parameters, use the correct function type to avoid indirect call
type mismatches with Control-Flow Integrity checking.

Signed-off-by: Sami Tolvanen <[email protected]>
Signed-off-by: Will Deacon <[email protected]>

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arm64: implement syscall wrappers

To minimize the risk of userspace-controlled values being used under
speculation, this patch adds pt_regs based syscall wrappers for arm64,
which pass the minimum s

arm64: implement syscall wrappers

To minimize the risk of userspace-controlled values being used under
speculation, this patch adds pt_regs based syscall wrappers for arm64,
which pass the minimum set of required userspace values to syscall
implementations. For each syscall, a wrapper which takes a pt_regs
argument is automatically generated, and this extracts the arguments
before calling the "real" syscall implementation.

Each syscall has three functions generated:

* __do_<compat_>sys_<name> is the "real" syscall implementation, with
the expected prototype.

* __se_<compat_>sys_<name> is the sign-extension/narrowing wrapper,
inherited from common code. This takes a series of long parameters,
casting each to the requisite types required by the "real" syscall
implementation in __do_<compat_>sys_<name>.

This wrapper *may* not be necessary on arm64 given the AAPCS rules on
unused register bits, but it seemed safer to keep the wrapper for now.

* __arm64_<compat_>_sys_<name> takes a struct pt_regs pointer, and
extracts *only* the relevant register values, passing these on to the
__se_<compat_>sys_<name> wrapper.

The syscall invocation code is updated to handle the calling convention
required by __arm64_<compat_>_sys_<name>, and passes a single struct
pt_regs pointer.

The compiler can fold the syscall implementation and its wrappers, such
that the overhead of this approach is minimized.

Note that we play games with sys_ni_syscall(). It can't be defined with
SYSCALL_DEFINE0() because we must avoid the possibility of error
injection. Additionally, there are a couple of locations where we need
to call it from C code, and we don't (currently) have a
ksys_ni_syscall(). While it has no wrapper, passing in a redundant
pt_regs pointer is benign per the AAPCS.

When ARCH_HAS_SYSCALL_WRAPPER is selected, no prototype is defines for
sys_ni_syscall(). Since we need to treat it differently for in-kernel
calls and the syscall tables, the prototype is defined as-required.

The wrappers are largely the same as their x86 counterparts, but
simplified as we don't have a variety of compat calling conventions that
require separate stubs. Unlike x86, we have some zero-argument compat
syscalls, and must define COMPAT_SYSCALL_DEFINE0() to ensure that these
are also given an __arm64_compat_sys_ prefix.

Signed-off-by: Mark Rutland <[email protected]>
Reviewed-by: Dominik Brodowski <[email protected]>
Reviewed-by: Catalin Marinas <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Will Deacon <[email protected]>
Signed-off-by: Will Deacon <[email protected]>

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