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| author | Simon Rettberg | 2022-05-11 10:41:01 +0200 |
|---|---|---|
| committer | Simon Rettberg | 2022-05-11 10:41:01 +0200 |
| commit | a12e3c379cf2e5946c7316259ef46736cdd5f222 (patch) | |
| tree | 49638dad528a4490e293ea4a0f87e39ce862a75b /src/arch/x86/prefix/libprefix.S | |
| parent | Local UEFI disk boot support (diff) | |
| parent | [cloud] Allow aws-import script to run on Python 3.6 (diff) | |
| download | ipxe-a12e3c379cf2e5946c7316259ef46736cdd5f222.tar.gz ipxe-a12e3c379cf2e5946c7316259ef46736cdd5f222.tar.xz ipxe-a12e3c379cf2e5946c7316259ef46736cdd5f222.zip | |
Merge branch 'master' into openslx
Diffstat (limited to 'src/arch/x86/prefix/libprefix.S')
| -rw-r--r-- | src/arch/x86/prefix/libprefix.S | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/src/arch/x86/prefix/libprefix.S b/src/arch/x86/prefix/libprefix.S index ffb211058..d7f261957 100644 --- a/src/arch/x86/prefix/libprefix.S +++ b/src/arch/x86/prefix/libprefix.S @@ -380,6 +380,11 @@ process_bytes: pushl %eax pushl %ebp + /* Construct ljmp code on stack (since .prefix may not be writable) */ + .equ LJMP_LEN, 0x06 + pushw %cs /* "nop ; ljmp %cs, $2f" */ + pushw $2f + pushw $0xea90 /* Construct GDT on stack (since .prefix may not be writable) */ .equ GDT_LEN, 0x20 .equ PM_DS, 0x18 /* Flat data segment */ @@ -410,8 +415,9 @@ process_bytes: pushw %es pushw %ds pushw %ss - pushw %cs - pushw $2f + pushw %ss /* Far pointer to ljmp code on stack */ + leaw (GDT_LEN + 1)(%bp), %ax + pushw %ax cli data32 lgdt (%bp) movl %cr0, %eax @@ -438,7 +444,7 @@ process_bytes: popfw movl %eax, %cr0 lret -2: /* lret will ljmp to here */ +2: /* lret will ljmp to here (via constructed ljmp on stack) */ popw %ss popw %ds popw %es @@ -461,7 +467,7 @@ process_bytes: /* Restore GDT */ data32 lgdt -8(%bp) - leaw GDT_LEN(%bp), %sp + leaw (GDT_LEN + LJMP_LEN)(%bp), %sp /* Restore registers and return */ popl %ebp |