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Kernel/riscv64: Don't disable stack protector and sanitizers

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I am not sure why 096cecb95e disabled the stack protector and sanitizers
for all files, but this is not necessary.
Only the pre_init code needs to run without them, as that code runs
identity mapped.
This commit is contained in:
Sönke Holz 2024-01-19 15:30:23 +01:00 • committed by Andrew Kaster
parent 900ec37f81
commit 0e6d87fe83
2 changed files with 25 additions and 2 deletions
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6
Kernel/Arch/riscv64/MMU.cpp
View file

@ -45,7 +45,11 @@ public:
u64* page = m_current;
m_current += (PAGE_TABLE_SIZE / sizeof(FlatPtr));
__builtin_memset(page, 0, PAGE_TABLE_SIZE);
// We can't use [__builtin_]memset here, as that would call into code which has stack protectors enabled,
// resulting in an access to an absolute address.
for (u64* p = page; p < page + (PAGE_TABLE_SIZE / sizeof(u64)); p++)
*p = 0;
return page;
}

21
Kernel/CMakeLists.txt
View file

@ -510,8 +510,19 @@ elseif("${SERENITY_ARCH}" STREQUAL "aarch64")
# by the compiler. The CPU cannot access global variables without the MMU as the kernel is linked for a virtual address in high memory.
set_source_files_properties(${SOURCES_RUNNING_WITHOUT_MMU} PROPERTIES COMPILE_FLAGS "-fno-stack-protector -fno-sanitize=all")
elseif("${SERENITY_ARCH}" STREQUAL "riscv64")
set(SOURCES_RUNNING_WITHOUT_MMU
Arch/riscv64/MMU.cpp
Arch/riscv64/pre_init.cpp
# FIXME: Don't disable stack protectors and sanitizers in SBI.cpp.
# Maybe implement SBI debug console printing directly in pre_init.cpp as well?
Arch/riscv64/SBI.cpp
)
set(KERNEL_SOURCES
${KERNEL_SOURCES}
${SOURCES_RUNNING_WITHOUT_MMU}
Arch/Processor.cpp
kprintf.cpp
@ -536,7 +547,15 @@ elseif("${SERENITY_ARCH}" STREQUAL "riscv64")
Arch/riscv64/Timer.cpp
)
add_compile_options(-fno-stack-protector -fno-sanitize=all)
# NOTE: These files cannot use a stack protector and sanitizers, as these will cause accesses to global variables to be inserted
# by the compiler. The CPU cannot access global variables without the MMU as the kernel is linked for a virtual address in high memory.
# On GCC, also prevent loops from being optimized into functions like memset, as those might use stack protectors and sanitizers.
# We also have to disable our -ftrivial-auto-var-init=pattern mitigation, as that would cause memsets to be inserted.
if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
set_source_files_properties(${SOURCES_RUNNING_WITHOUT_MMU} PROPERTIES COMPILE_FLAGS "-fno-stack-protector -fno-sanitize=all -ftrivial-auto-var-init=uninitialized -fno-tree-loop-distribution -fno-tree-loop-distribute-patterns")
else()
set_source_files_properties(${SOURCES_RUNNING_WITHOUT_MMU} PROPERTIES COMPILE_FLAGS "-fno-stack-protector -fno-sanitize=all -ftrivial-auto-var-init=uninitialized")
endif()
endif()
set(AK_SOURCES