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Kernel: Fix memset() on x86_64

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Previously memset() only set half of the bytes to the requested value.
This commit is contained in:
Gunnar Beutner 2021-06-28 13:44:38 +02:00 committed by Andreas Kling
parent cdcb75709a
commit e56a0d6af7
Notes: sideshowbarker 2024-07-18 11:25:08 +09:00 
Author: https://github.com/gunnarbeutner
Commit: https://github.com/SerenityOS/serenity/commit/e56a0d6af70
Pull-request: https://github.com/SerenityOS/serenity/pull/8290
Reviewed-by: https://github.com/Hendiadyoin1
2 changed files with 18 additions and 8 deletions
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14
AK/Types.h
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@ -65,14 +65,24 @@ namespace std {
using nullptr_t = decltype(nullptr);
}
static constexpr u32 explode_byte(u8 b)
static constexpr FlatPtr explode_byte(u8 b)
{
return b << 24 | b << 16 | b << 8 | b;
#if ARCH(I386)
return (u32)b << 24 | (u32)b << 16 | (u32)b << 8 | (u32)b;
#else
return (u64)b << 56 | (u64)b << 48 | (u64)b << 40 | (u64)b << 32 | (u64)b << 24 | (u64)b << 16 | (u64)b << 8 | (u64)b;
#endif
}
#if ARCH(I386)
static_assert(explode_byte(0xff) == 0xffffffff);
static_assert(explode_byte(0x80) == 0x80808080);
static_assert(explode_byte(0x7f) == 0x7f7f7f7f);
#else
static_assert(explode_byte(0xff) == 0xffffffffffffffff);
static_assert(explode_byte(0x80) == 0x8080808080808080);
static_assert(explode_byte(0x7f) == 0x7f7f7f7f7f7f7f7f);
#endif
static_assert(explode_byte(0) == 0);
constexpr size_t align_up_to(const size_t value, const size_t alignment)

12
Kernel/Arch/x86/common/Interrupts.cpp
View file

@ -356,12 +356,12 @@ void page_fault_handler(TrapFrame* trap)
regs.exception_code & PageFaultFlags::InstructionFetch ? "instruction fetch / " : "",
regs.exception_code & PageFaultFlags::Write ? "write to" : "read from",
VirtualAddress(fault_address));
u32 malloc_scrub_pattern = explode_byte(MALLOC_SCRUB_BYTE);
u32 free_scrub_pattern = explode_byte(FREE_SCRUB_BYTE);
u32 kmalloc_scrub_pattern = explode_byte(KMALLOC_SCRUB_BYTE);
u32 kfree_scrub_pattern = explode_byte(KFREE_SCRUB_BYTE);
u32 slab_alloc_scrub_pattern = explode_byte(SLAB_ALLOC_SCRUB_BYTE);
u32 slab_dealloc_scrub_pattern = explode_byte(SLAB_DEALLOC_SCRUB_BYTE);
FlatPtr malloc_scrub_pattern = explode_byte(MALLOC_SCRUB_BYTE);
FlatPtr free_scrub_pattern = explode_byte(FREE_SCRUB_BYTE);
FlatPtr kmalloc_scrub_pattern = explode_byte(KMALLOC_SCRUB_BYTE);
FlatPtr kfree_scrub_pattern = explode_byte(KFREE_SCRUB_BYTE);
FlatPtr slab_alloc_scrub_pattern = explode_byte(SLAB_ALLOC_SCRUB_BYTE);
FlatPtr slab_dealloc_scrub_pattern = explode_byte(SLAB_DEALLOC_SCRUB_BYTE);
if ((fault_address & 0xffff0000) == (malloc_scrub_pattern & 0xffff0000)) {
dbgln("Note: Address {} looks like it may be uninitialized malloc() memory", VirtualAddress(fault_address));
} else if ((fault_address & 0xffff0000) == (free_scrub_pattern & 0xffff0000)) {