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Kernel: Clear the x86 DF flag when entering the kernel

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The SysV ABI says that the DF flag should be clear on function entry.
That means we have to clear it when jumping into the kernel from some
random userspace context.
This commit is contained in:
Andreas Kling 2019-11-09 22:40:35 +01:00
parent fbeb1ab15b
commit b285a1944e
Notes: sideshowbarker 2024-07-19 11:17:53 +09:00
3 changed files with 33 additions and 28 deletions
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59
Kernel/Arch/i386/CPU.cpp
View file

@ -55,6 +55,7 @@ asm(
" pushw %ss\n"
" popw %ds\n"
" popw %es\n"
" cld\n"
" call handle_irq\n"
" popw %es\n"
" popw %ds\n"
@ -82,6 +83,7 @@ asm(
" popw %es\n" \
" popw %fs\n" \
" popw %gs\n" \
" cld\n" \
" call exception_" #ec "_handler\n" \
" popw %gs\n" \
" popw %gs\n" \
@ -92,35 +94,36 @@ asm(
" add $0x4, %esp\n" \
" iret\n");
#define EH_ENTRY_NO_CODE(ec) \
#define EH_ENTRY_NO_CODE(ec) \
extern "C" void exception_##ec##_handler(RegisterDump); \
extern "C" void exception_##ec##_entry(); \
asm( \
".globl exception_" #ec "_entry\n" \
"exception_" #ec "_entry: \n" \
" pushl $0x0\n" \
" pusha\n" \
" pushw %ds\n" \
" pushw %es\n" \
" pushw %fs\n" \
" pushw %gs\n" \
" pushw %ss\n" \
" pushw %ss\n" \
" pushw %ss\n" \
" pushw %ss\n" \
" pushw %ss\n" \
" popw %ds\n" \
" popw %es\n" \
" popw %fs\n" \
" popw %gs\n" \
" call exception_" #ec "_handler\n" \
" popw %gs\n" \
" popw %gs\n" \
" popw %fs\n" \
" popw %es\n" \
" popw %ds\n" \
" popa\n" \
" add $0x4, %esp\n" \
extern "C" void exception_##ec##_entry(); \
asm( \
".globl exception_" #ec "_entry\n" \
"exception_" #ec "_entry: \n" \
" pushl $0x0\n" \
" pusha\n" \
" pushw %ds\n" \
" pushw %es\n" \
" pushw %fs\n" \
" pushw %gs\n" \
" pushw %ss\n" \
" pushw %ss\n" \
" pushw %ss\n" \
" pushw %ss\n" \
" pushw %ss\n" \
" popw %ds\n" \
" popw %es\n" \
" popw %fs\n" \
" popw %gs\n" \
" cld\n" \
" call exception_" #ec "_handler\n" \
" popw %gs\n" \
" popw %gs\n" \
" popw %fs\n" \
" popw %es\n" \
" popw %ds\n" \
" popa\n" \
" add $0x4, %esp\n" \
" iret\n");
static void dump(const RegisterDump& regs)

1
Kernel/Arch/i386/PIT.cpp
View file

@ -27,6 +27,7 @@ asm(
" popw %es\n"
" popw %fs\n"
" popw %gs\n"
" cld\n"
" call timer_interrupt_handler\n"
" popw %gs\n"
" popw %gs\n"

1
Kernel/Syscall.cpp
View file

@ -24,6 +24,7 @@ asm(
" popw %es\n"
" popw %fs\n"
" popw %gs\n"
" cld\n"
" call syscall_trap_entry\n"
" popw %gs\n"
" popw %gs\n"