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| author | Michael Brown | 2016-02-21 02:01:28 +0100 |
|---|---|---|
| committer | Michael Brown | 2016-02-21 02:01:28 +0100 |
| commit | 5fbfe50ccbbafe2f6bebd45e927bf7f9e23846dd (patch) | |
| tree | b81de4bd233b6205b9085582a95643c05db487d3 /src/arch | |
| parent | [librm] Add phys_call() wrapper for calling code with physical addressing (diff) | |
| download | ipxe-5fbfe50ccbbafe2f6bebd45e927bf7f9e23846dd.tar.gz ipxe-5fbfe50ccbbafe2f6bebd45e927bf7f9e23846dd.tar.xz ipxe-5fbfe50ccbbafe2f6bebd45e927bf7f9e23846dd.zip | |
[librm] Do not preserve flags unnecessarily
No callers of prot_to_phys, phys_to_prot, or intr_to_prot require the
flags to be preserved. Remove the unnecessary pushfl/popfl pairs.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Diffstat (limited to 'src/arch')
| -rw-r--r-- | src/arch/x86/transitions/librm.S | 28 |
1 files changed, 11 insertions, 17 deletions
diff --git a/src/arch/x86/transitions/librm.S b/src/arch/x86/transitions/librm.S index ab4994fb..a3046987 100644 --- a/src/arch/x86/transitions/librm.S +++ b/src/arch/x86/transitions/librm.S @@ -506,7 +506,7 @@ rm_gdtr: * * Switch from 32-bit protected mode with physical addresses to 32-bit * protected mode with virtual addresses. %esp is adjusted to a - * virtual address. All other registers and flags are preserved. + * virtual address. All other registers are preserved. * * The return address for this function should be a 32-bit physical * (sic) address. @@ -517,8 +517,7 @@ rm_gdtr: .code32 .globl phys_to_prot phys_to_prot: - /* Preserve registers and flags */ - pushfl + /* Preserve registers */ pushl %eax pushl %ebp @@ -537,12 +536,11 @@ phys_to_prot: subl %ebp, %esp /* Adjust return address to a virtual address */ - subl %ebp, 12(%esp) + subl %ebp, 8(%esp) - /* Restore registers and flags, and return */ + /* Restore registers and return */ popl %ebp popl %eax - popfl ret /* Expose as _phys_to_virt for use by COMBOOT */ @@ -554,7 +552,7 @@ phys_to_prot: * * Switch from 32-bit protected mode with virtual addresses to 32-bit * protected mode with physical addresses. %esp is adjusted to a - * physical address. All other registers and flags are preserved. + * physical address. All other registers are preserved. * * The return address for this function should be a 32-bit virtual * (sic) address. @@ -564,14 +562,13 @@ phys_to_prot: .section ".text.prot_to_phys", "ax", @progbits .code32 prot_to_phys: - /* Preserve registers and flags */ - pushfl + /* Preserve registers */ pushl %eax pushl %ebp /* Adjust return address to a physical address */ movl VIRTUAL(virt_offset), %ebp - addl %ebp, 12(%esp) + addl %ebp, 8(%esp) /* Switch to physical code segment */ cli @@ -589,10 +586,9 @@ prot_to_phys: movw %ax, %ss addl %ebp, %esp - /* Restore registers and flags, and return */ + /* Restore registers and return */ popl %ebp popl %eax - popfl ret /* Expose as _virt_to_phys for use by COMBOOT */ @@ -605,7 +601,7 @@ prot_to_phys: * Switch from 32-bit protected mode with a virtual code segment and * either a physical or virtual stack segment to 32-bit protected mode * with normal virtual addresses. %esp is adjusted if necessary to a - * virtual address. All other registers and flags are preserved. + * virtual address. All other registers are preserved. * * The return address for this function should be a 32-bit virtual * address. @@ -616,8 +612,7 @@ prot_to_phys: .code32 .globl intr_to_prot intr_to_prot: - /* Preserve registers and flags */ - pushfl + /* Preserve registers */ pushl %eax /* Check whether stack segment is physical or virtual */ @@ -636,9 +631,8 @@ intr_to_prot: movw %ax, %ss subl VIRTUAL(virt_offset), %esp 1: - /* Restore registers and flags, and return */ + /* Restore registers and return */ popl %eax - popfl ret /* Expose as _intr_to_virt for use by GDB */ |