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| author | dzwdz | 2021-07-21 21:35:20 +0200 |
|---|---|---|
| committer | dzwdz | 2021-07-21 21:35:20 +0200 |
| commit | 8a168f2be5d90f972975abf0b40145a75c0231b7 (patch) | |
| tree | cdfcd84a132a6a9864b01b626cc670e9caf7c4ef /src/kernel/arch/i386/sysenter.s | |
| parent | 36089d20ca1f7c57f36c4172759a5084bdf87a3a (diff) | |
syscall parameter & return value passing
Sadly, sysenter on i386 limits me to only 4 arguments (so, 1 for the
syscall id + 3 real args). If that turns out to be an issue I'll either
just switch to interrupts, or switch to x64.
Diffstat (limited to 'src/kernel/arch/i386/sysenter.s')
| -rw-r--r-- | src/kernel/arch/i386/sysenter.s | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/src/kernel/arch/i386/sysenter.s b/src/kernel/arch/i386/sysenter.s index 3fcd4c3..7375e06 100644 --- a/src/kernel/arch/i386/sysenter.s +++ b/src/kernel/arch/i386/sysenter.s @@ -49,6 +49,10 @@ sysenter_setup: sysenter_handler: pushal + push %edi + push %esi + push %ebx + push %eax mov %cr0, %eax and $0x7FFFFFFF, %eax // disable paging @@ -56,9 +60,14 @@ sysenter_handler: call syscall_handler + // save the return value + mov %eax, 44(%esp) // 16 [top of eflags] + 7*4 [skip until EAX] + mov %edx, 32(%esp) // 16 + 4*4 [skip until EBX] + mov %cr0, %eax or $0x80000000, %eax // enable paging mov %eax, %cr0 + add $16, %esp popal sysexit |