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2024-12-03arm64: patching: avoid early page_to_phys()Mark Rutland
When arm64 is configured with CONFIG_DEBUG_VIRTUAL=y, a warning is printed from the patching code because patch_map(), e.g. | ------------[ cut here ]------------ | WARNING: CPU: 0 PID: 0 at arch/arm64/kernel/patching.c:45 patch_map.constprop.0+0x120/0xd00 | CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 6.13.0-rc1-00002-ge1a5d6c6be55 #1 | Hardware name: linux,dummy-virt (DT) | pstate: 800003c5 (Nzcv DAIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--) | pc : patch_map.constprop.0+0x120/0xd00 | lr : patch_map.constprop.0+0x120/0xd00 | sp : ffffa9bb312a79a0 | x29: ffffa9bb312a79a0 x28: 0000000000000001 x27: 0000000000000001 | x26: 0000000000000000 x25: 0000000000000000 x24: 00000000000402e8 | x23: ffffa9bb2c94c1c8 x22: ffffa9bb2c94c000 x21: ffffa9bb222e883c | x20: 0000000000000002 x19: ffffc1ffc100ba40 x18: ffffa9bb2cf0f21c | x17: 0000000000000006 x16: 0000000000000000 x15: 0000000000000004 | x14: 1ffff5376625b4ac x13: ffff753766a67fb8 x12: ffff753766919cd1 | x11: 0000000000000003 x10: 1ffff5376625b4c3 x9 : 1ffff5376625b4af | x8 : ffff753766254f0a x7 : 0000000041b58ab3 x6 : ffff753766254f18 | x5 : ffffa9bb312d9bc0 x4 : 0000000000000000 x3 : ffffa9bb29bd90e4 | x2 : 0000000000000002 x1 : ffffa9bb312d9bc0 x0 : 0000000000000000 | Call trace: | patch_map.constprop.0+0x120/0xd00 (P) | patch_map.constprop.0+0x120/0xd00 (L) | __aarch64_insn_write+0xa8/0x120 | aarch64_insn_patch_text_nosync+0x4c/0xb8 | arch_jump_label_transform_queue+0x7c/0x100 | jump_label_update+0x154/0x460 | static_key_enable_cpuslocked+0x1d8/0x280 | static_key_enable+0x2c/0x48 | early_randomize_kstack_offset+0x104/0x168 | do_early_param+0xe4/0x148 | parse_args+0x3a4/0x838 | parse_early_options+0x50/0x68 | parse_early_param+0x58/0xe0 | setup_arch+0x78/0x1f0 | start_kernel+0xa0/0x530 | __primary_switched+0x8c/0xa0 | irq event stamp: 0 | hardirqs last enabled at (0): [<0000000000000000>] 0x0 | hardirqs last disabled at (0): [<0000000000000000>] 0x0 | softirqs last enabled at (0): [<0000000000000000>] 0x0 | softirqs last disabled at (0): [<0000000000000000>] 0x0 | ---[ end trace 0000000000000000 ]--- The warning has been produced since commit: 3e25d5a49f99b75b ("asm-generic: add an optional pfn_valid check to page_to_phys") ... which added a pfn_valid() check into page_to_phys(), and at this point in boot pfn_valid() will always return false because the vmemmap has not yet been initialized and there are no valid mem_sections yet. Before that commit, the arithmetic performed by page_to_phys() would give the expected physical address, though it is somewhat dubious to use vmemmap addresses before the vmemmap has been initialized. Aside from kernel image addresses, all executable code should be allocated from execmem (where all allocations will fall within the vmalloc area), and so there's no need for the fallback case when CONFIG_EXECMEM=n. Simplify patch_map() accordingly, directly converting kernel image addresses and removing the redundant fallback case. Fixes: 3e25d5a49f99 ("asm-generic: add an optional pfn_valid check to page_to_phys") Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Christoph Hellwig <hch@lst.de> Cc: Mike Rapoport <rppt@kernel.org> Cc: Thomas Huth <thuth@redhat.com> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20241202170359.1475019-1-mark.rutland@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2024-11-07asm-generic: introduce text-patching.hMike Rapoport (Microsoft)
Several architectures support text patching, but they name the header files that declare patching functions differently. Make all such headers consistently named text-patching.h and add an empty header in asm-generic for architectures that do not support text patching. Link: https://lkml.kernel.org/r/20241023162711.2579610-4-rppt@kernel.org Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> # m68k Acked-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> Tested-by: kdevops <kdevops@lists.linux.dev> Cc: Andreas Larsson <andreas@gaisler.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Borislav Petkov (AMD) <bp@alien8.de> Cc: Brian Cain <bcain@quicinc.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Dinh Nguyen <dinguyen@kernel.org> Cc: Guo Ren <guoren@kernel.org> Cc: Helge Deller <deller@gmx.de> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: Liam R. Howlett <Liam.Howlett@Oracle.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org> Cc: Matt Turner <mattst88@gmail.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Simek <monstr@monstr.eu> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Richard Weinberger <richard@nod.at> Cc: Russell King <linux@armlinux.org.uk> Cc: Song Liu <song@kernel.org> Cc: Stafford Horne <shorne@gmail.com> Cc: Steven Rostedt (Google) <rostedt@goodmis.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Uladzislau Rezki (Sony) <urezki@gmail.com> Cc: Vineet Gupta <vgupta@kernel.org> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-05-24arm64: patching: fix handling of execmem addressesWill Deacon
Klara Modin reported warnings for a kernel configured with BPF_JIT but without MODULES: [ 44.131296] Trying to vfree() bad address (000000004a17c299) [ 44.138024] WARNING: CPU: 1 PID: 193 at mm/vmalloc.c:3189 remove_vm_area (mm/vmalloc.c:3189 (discriminator 1)) [ 44.146675] CPU: 1 PID: 193 Comm: kworker/1:2 Tainted: G D W 6.9.0-01786-g2c9e5d4a0082 #25 [ 44.158229] Hardware name: Raspberry Pi 3 Model B (DT) [ 44.164433] Workqueue: events bpf_prog_free_deferred [ 44.170492] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 44.178601] pc : remove_vm_area (mm/vmalloc.c:3189 (discriminator 1)) [ 44.183705] lr : remove_vm_area (mm/vmalloc.c:3189 (discriminator 1)) [ 44.188772] sp : ffff800082a13c70 [ 44.193112] x29: ffff800082a13c70 x28: 0000000000000000 x27: 0000000000000000 [ 44.201384] x26: 0000000000000000 x25: ffff00003a44efa0 x24: 00000000d4202000 [ 44.209658] x23: ffff800081223dd0 x22: ffff00003a198a40 x21: ffff8000814dd880 [ 44.217924] x20: 00000000d4202000 x19: ffff8000814dd880 x18: 0000000000000006 [ 44.226206] x17: 0000000000000000 x16: 0000000000000020 x15: 0000000000000002 [ 44.234460] x14: ffff8000811a6370 x13: 0000000020000000 x12: 0000000000000000 [ 44.242710] x11: ffff8000811a6370 x10: 0000000000000144 x9 : ffff8000811fe370 [ 44.250959] x8 : 0000000000017fe8 x7 : 00000000fffff000 x6 : ffff8000811fe370 [ 44.259206] x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000000 [ 44.267457] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff000002203240 [ 44.275703] Call trace: [ 44.279158] remove_vm_area (mm/vmalloc.c:3189 (discriminator 1)) [ 44.283858] vfree (mm/vmalloc.c:3322) [ 44.287835] execmem_free (mm/execmem.c:70) [ 44.292347] bpf_jit_free_exec+0x10/0x1c [ 44.297283] bpf_prog_pack_free (kernel/bpf/core.c:1006) [ 44.302457] bpf_jit_binary_pack_free (kernel/bpf/core.c:1195) [ 44.307951] bpf_jit_free (include/linux/filter.h:1083 arch/arm64/net/bpf_jit_comp.c:2474) [ 44.312342] bpf_prog_free_deferred (kernel/bpf/core.c:2785) [ 44.317785] process_one_work (kernel/workqueue.c:3273) [ 44.322684] worker_thread (kernel/workqueue.c:3342 (discriminator 2) kernel/workqueue.c:3429 (discriminator 2)) [ 44.327292] kthread (kernel/kthread.c:388) [ 44.331342] ret_from_fork (arch/arm64/kernel/entry.S:861) The problem is because bpf_arch_text_copy() silently fails to write to the read-only area as a result of patch_map() faulting and the resulting -EFAULT being chucked away. Update patch_map() to use CONFIG_EXECMEM instead of CONFIG_STRICT_MODULE_RWX to check for vmalloc addresses. Link: https://lkml.kernel.org/r/20240521213813.703309-1-rppt@kernel.org Fixes: 2c9e5d4a0082 ("bpf: remove CONFIG_BPF_JIT dependency on CONFIG_MODULES of") Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org> Reported-by: Klara Modin <klarasmodin@gmail.com> Closes: https://lore.kernel.org/all/7983fbbf-0127-457c-9394-8d6e4299c685@gmail.com Tested-by: Klara Modin <klarasmodin@gmail.com> Cc: Björn Töpel <bjorn@kernel.org> Cc: Luis Chamberlain <mcgrof@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-02-28arm64: patching: implement text_poke APIPuranjay Mohan
The text_poke API is used to implement functions like memcpy() and memset() for instruction memory (RO+X). The implementation is similar to the x86 version. This will be used by the BPF JIT to write and modify BPF programs. There could be more users of this in the future. Signed-off-by: Puranjay Mohan <puranjay12@gmail.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Link: https://lore.kernel.org/r/20240228141824.119877-2-puranjay12@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-01-24arm64: patching: Add aarch64_insn_write_literal_u64()Mark Rutland
In subsequent patches we'll need to atomically write to a naturally-aligned 64-bit literal embedded within the kernel text. Add a helper for this. For consistency with other text patching code we use copy_to_kernel_nofault(), which is atomic for naturally-aligned accesses up to 64-bits. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Florent Revest <revest@chromium.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20230123134603.1064407-7-mark.rutland@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2022-04-08arm64: patch_text: Fixup last cpu should be masterGuo Ren
These patch_text implementations are using stop_machine_cpuslocked infrastructure with atomic cpu_count. The original idea: When the master CPU patch_text, the others should wait for it. But current implementation is using the first CPU as master, which couldn't guarantee the remaining CPUs are waiting. This patch changes the last CPU as the master to solve the potential risk. Fixes: ae16480785de ("arm64: introduce interfaces to hotpatch kernel and module code") Signed-off-by: Guo Ren <guoren@linux.alibaba.com> Signed-off-by: Guo Ren <guoren@kernel.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20220407073323.743224-2-guoren@kernel.org Signed-off-by: Will Deacon <will@kernel.org>
2021-06-24Merge branch 'for-next/insn' into for-next/coreWill Deacon
Refactoring of our instruction decoding routines and addition of some missing encodings. * for-next/insn: arm64: insn: avoid circular include dependency arm64: insn: move AARCH64_INSN_SIZE into <asm/insn.h> arm64: insn: decouple patching from insn code arm64: insn: Add load/store decoding helpers arm64: insn: Add some opcodes to instruction decoder arm64: insn: Add barrier encodings arm64: insn: Add SVE instruction class arm64: Move instruction encoder/decoder under lib/ arm64: Move aarch32 condition check functions arm64: Move patching utilities out of instruction encoding/decoding
2021-06-11arm64: insn: move AARCH64_INSN_SIZE into <asm/insn.h>Mark Rutland
For histroical reasons, we define AARCH64_INSN_SIZE in <asm/alternative-macros.h>, but it would make more sense to do so in <asm/insn.h>. Let's move it into <asm/insn.h>, and add the necessary include directives for this. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20210609102301.17332-3-mark.rutland@arm.com Signed-off-by: Will Deacon <will@kernel.org>
2021-06-11arm64: insn: decouple patching from insn codeMark Rutland
Currently, <asm/insn.h> includes <asm/patching.h>. We intend that <asm/insn.h> will be usable from userspace, so it doesn't make sense to include headers for kernel-only features such as the patching routines, and we'd intended to restrict <asm/insn.h> to instruction encoding details. Let's decouple the patching code from <asm/insn.h>, and explicitly include <asm/patching.h> where it is needed. Since <asm/patching.h> isn't included from assembly, we can drop the __ASSEMBLY__ guards. At the same time, sort the kprobes includes so that it's easier to see what is and isn't incldued. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20210609102301.17332-2-mark.rutland@arm.com Signed-off-by: Will Deacon <will@kernel.org>
2021-05-27arm64: Move patching utilities out of instruction encoding/decodingJulien Thierry
Files insn.[c|h] containt some functions used for instruction patching. In order to reuse the instruction encoder/decoder, move the patching utilities to their own file. Signed-off-by: Julien Thierry <jthierry@redhat.com> Link: https://lore.kernel.org/r/20210303170536.1838032-2-jthierry@redhat.com [will: Include patching.h in insn.h to fix header mess; add __ASSEMBLY__ guards] Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Will Deacon <will@kernel.org>