riscv/purgatory: Disable CFI

Filter out CC_FLAGS_CFI when CONFIG_CFI_CLANG.

Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Sami Tolva

riscv/purgatory: Disable CFI

Filter out CC_FLAGS_CFI when CONFIG_CFI_CLANG.

Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Link: https://lore.kernel.org/r/20230710183544.999540-13-samitolvanen@google.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

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riscv/purgatory: remove PGO flags

If profile-guided optimization is enabled, the purgatory ends up with
multiple .text sections. This is not supported by kexec and crashes the
system.

Link: https:

riscv/purgatory: remove PGO flags

If profile-guided optimization is enabled, the purgatory ends up with
multiple .text sections. This is not supported by kexec and crashes the
system.

Link: https://lkml.kernel.org/r/20230321-kexec_clang16-v7-4-b05c520b7296@chromium.org
Fixes: 930457057abe ("kernel/kexec_file.c: split up __kexec_load_puragory")
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Cc: <stable@vger.kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Philipp Rudo <prudo@redhat.com>
Cc: Ross Zwisler <zwisler@google.com>
Cc: Simon Horman <horms@kernel.org>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tom Rix <trix@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

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riscv/purgatory: Do not use fortified string functions

With the addition of -fstrict-flex-arrays=3, struct sha256_state's
trailing array is no longer ignored by CONFIG_FORTIFY_SOURCE:

struct sha256

riscv/purgatory: Do not use fortified string functions

With the addition of -fstrict-flex-arrays=3, struct sha256_state's
trailing array is no longer ignored by CONFIG_FORTIFY_SOURCE:

struct sha256_state {
u32 state[SHA256_DIGEST_SIZE / 4];
u64 count;
u8 buf[SHA256_BLOCK_SIZE];
};

This means that the memcpy() calls with "buf" as a destination in
sha256.c's code will attempt to perform run-time bounds checking, which
could lead to calling missing functions, specifically a potential
WARN_ONCE, which isn't callable from purgatory.

Reported-by: Thorsten Leemhuis <linux@leemhuis.info>
Closes: https://lore.kernel.org/lkml/175578ec-9dec-7a9c-8d3a-43f24ff86b92@leemhuis.info/
Bisected-by: "Joan Bruguera Micó" <joanbrugueram@gmail.com>
Fixes: df8fc4e934c1 ("kbuild: Enable -fstrict-flex-arrays=3")
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Conor Dooley <conor.dooley@microchip.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Alyssa Ross <hi@alyssa.is>
Cc: Heiko Stuebner <heiko.stuebner@vrull.eu>
Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc: linux-riscv@lists.infradead.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Link: https://lore.kernel.org/r/20230601160025.gonna.868-kees@kernel.org

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purgatory: fix disabling debug info

Since 32ef9e5054ec, -Wa,-gdwarf-2 is no longer used in KBUILD_AFLAGS.
Instead, it includes -g, the appropriate -gdwarf-* flag, and also the
-Wa versions of both o

purgatory: fix disabling debug info

Since 32ef9e5054ec, -Wa,-gdwarf-2 is no longer used in KBUILD_AFLAGS.
Instead, it includes -g, the appropriate -gdwarf-* flag, and also the
-Wa versions of both of those if building with Clang and GNU as. As a
result, debug info was being generated for the purgatory objects, even
though the intention was that it not be.

Fixes: 32ef9e5054ec ("Makefile.debug: re-enable debug info for .S files")
Signed-off-by: Alyssa Ross <hi@alyssa.is>
Cc: stable@vger.kernel.org
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

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RISC-V: add infrastructure to allow different str* implementations

Depending on supported extensions on specific RISC-V cores,
optimized str* functions might make sense.

This adds basic infrastruct

RISC-V: add infrastructure to allow different str* implementations

Depending on supported extensions on specific RISC-V cores,
optimized str* functions might make sense.

This adds basic infrastructure to allow patching the function calls
via alternatives later on.

The Linux kernel provides standard implementations for string functions
but when architectures want to extend them, they need to provide their
own.

The added generic string functions are done in assembler (taken from
disassembling the main-kernel functions for now) to allow us to control
the used registers and extend them with optimized variants.

This doesn't override the compiler's use of builtin replacements. So still
first of all the compiler will select if a builtin will be better suitable
i.e. for known strings. For all regular cases we will want to later
select possible optimized variants and in the worst case fall back to the
generic implemention added with this change.

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230113212301.3534711-2-heiko@sntech.de
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

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riscv/purgatory: Omit use of bin2c

The .incbin assembler directive is much faster than bin2c + $(CC).

Do similar refactoring as in commit 4c0f032d4963 ("s390/purgatory:
Omit use of bin2c").

Please

riscv/purgatory: Omit use of bin2c

The .incbin assembler directive is much faster than bin2c + $(CC).

Do similar refactoring as in commit 4c0f032d4963 ("s390/purgatory:
Omit use of bin2c").

Please note the .quad directive matches to size_t in C (both 8 byte)
because the purgatory is compiled only for the 64-bit kernel.
(KEXEC_FILE depends on 64BIT).

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/r/20220625223438.835408-2-masahiroy@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

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riscv/purgatory: hard-code obj-y in Makefile

The purgatory/ directory is entirely guarded in arch/riscv/Kbuild.
CONFIG_ARCH_HAS_KEXEC_PURGATORY is bool type.

$(CONFIG_ARCH_HAS_KEXEC_PURGATORY) is a

riscv/purgatory: hard-code obj-y in Makefile

The purgatory/ directory is entirely guarded in arch/riscv/Kbuild.
CONFIG_ARCH_HAS_KEXEC_PURGATORY is bool type.

$(CONFIG_ARCH_HAS_KEXEC_PURGATORY) is always 'y' when Kbuild visits
this Makefile for building.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/r/20220625223438.835408-1-masahiroy@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

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RISC-V: Add purgatory

This patch adds purgatory, the name and concept have been taken
from kexec-tools. Purgatory runs between two kernels, and do
verify sha256 hash to ensure the kernel to jump to

RISC-V: Add purgatory

This patch adds purgatory, the name and concept have been taken
from kexec-tools. Purgatory runs between two kernels, and do
verify sha256 hash to ensure the kernel to jump to is fine and
has not been corrupted after loading. Makefile is modified based
on x86 platform.

Signed-off-by: Li Zhengyu <lizhengyu3@huawei.com>
Link: https://lore.kernel.org/r/20220408100914.150110-6-lizhengyu3@huawei.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

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