[PATCH v4 06/27] x86/entry/64: Adapt assembly for PIE support
Change the assembly code to use only relative references of symbols for the kernel to be PIE compatible. Position Independent Executable (PIE) support will allow to extend the KASLR randomization range 0x8000. Signed-off-by: Thomas Garnier --- arch/x86/entry/entry_64.S| 18 -- arch/x86/kernel/relocate_kernel_64.S | 8 +++- 2 files changed, 15 insertions(+), 11 deletions(-) diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 3166b9674429..1cbf4c3616a8 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -191,7 +191,7 @@ ENTRY(entry_SYSCALL_64_trampoline) * spill RDI and restore it in a second-stage trampoline. */ pushq %rdi - movq$entry_SYSCALL_64_stage2, %rdi + movabsq $entry_SYSCALL_64_stage2, %rdi JMP_NOSPEC %rdi END(entry_SYSCALL_64_trampoline) @@ -1276,7 +1276,8 @@ ENTRY(error_entry) movl%ecx, %eax /* zero extend */ cmpq%rax, RIP+8(%rsp) je .Lbstep_iret - cmpq$.Lgs_change, RIP+8(%rsp) + leaq.Lgs_change(%rip), %rcx + cmpq%rcx, RIP+8(%rsp) jne .Lerror_entry_done /* @@ -1481,10 +1482,10 @@ ENTRY(nmi) * resume the outer NMI. */ - movq$repeat_nmi, %rdx + leaqrepeat_nmi(%rip), %rdx cmpq8(%rsp), %rdx ja 1f - movq$end_repeat_nmi, %rdx + leaqend_repeat_nmi(%rip), %rdx cmpq8(%rsp), %rdx ja nested_nmi_out 1: @@ -1538,7 +1539,8 @@ nested_nmi: pushq %rdx pushfq pushq $__KERNEL_CS - pushq $repeat_nmi + leaqrepeat_nmi(%rip), %rdx + pushq %rdx /* Put stack back */ addq$(6*8), %rsp @@ -1577,7 +1579,11 @@ first_nmi: addq$8, (%rsp) /* Fix up RSP */ pushfq /* RFLAGS */ pushq $__KERNEL_CS/* CS */ - pushq $1f /* RIP */ + pushq $0 /* Futur return address */ + pushq %rax/* Save RAX */ + leaq1f(%rip), %rax /* RIP */ + movq%rax, 8(%rsp) /* Put 1f on return address */ + popq%rax/* Restore RAX */ iretq /* continues at repeat_nmi below */ UNWIND_HINT_IRET_REGS 1: diff --git a/arch/x86/kernel/relocate_kernel_64.S b/arch/x86/kernel/relocate_kernel_64.S index a7227dfe1a2b..0c0fc259a4e2 100644 --- a/arch/x86/kernel/relocate_kernel_64.S +++ b/arch/x86/kernel/relocate_kernel_64.S @@ -208,11 +208,9 @@ identity_mapped: movq%rax, %cr3 lea PAGE_SIZE(%r8), %rsp callswap_pages - jmp *virtual_mapped_addr(%rip) - - /* Absolute value for PIE support */ -virtual_mapped_addr: - .quad virtual_mapped + movabsq $virtual_mapped, %rax + pushq %rax + ret virtual_mapped: movqRSP(%r8), %rsp -- 2.17.0.921.gf22659ad46-goog
[PATCH v4 06/27] x86/entry/64: Adapt assembly for PIE support
Change the assembly code to use only relative references of symbols for the kernel to be PIE compatible. Position Independent Executable (PIE) support will allow to extend the KASLR randomization range 0x8000. Signed-off-by: Thomas Garnier --- arch/x86/entry/entry_64.S| 18 -- arch/x86/kernel/relocate_kernel_64.S | 8 +++- 2 files changed, 15 insertions(+), 11 deletions(-) diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 3166b9674429..1cbf4c3616a8 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -191,7 +191,7 @@ ENTRY(entry_SYSCALL_64_trampoline) * spill RDI and restore it in a second-stage trampoline. */ pushq %rdi - movq$entry_SYSCALL_64_stage2, %rdi + movabsq $entry_SYSCALL_64_stage2, %rdi JMP_NOSPEC %rdi END(entry_SYSCALL_64_trampoline) @@ -1276,7 +1276,8 @@ ENTRY(error_entry) movl%ecx, %eax /* zero extend */ cmpq%rax, RIP+8(%rsp) je .Lbstep_iret - cmpq$.Lgs_change, RIP+8(%rsp) + leaq.Lgs_change(%rip), %rcx + cmpq%rcx, RIP+8(%rsp) jne .Lerror_entry_done /* @@ -1481,10 +1482,10 @@ ENTRY(nmi) * resume the outer NMI. */ - movq$repeat_nmi, %rdx + leaqrepeat_nmi(%rip), %rdx cmpq8(%rsp), %rdx ja 1f - movq$end_repeat_nmi, %rdx + leaqend_repeat_nmi(%rip), %rdx cmpq8(%rsp), %rdx ja nested_nmi_out 1: @@ -1538,7 +1539,8 @@ nested_nmi: pushq %rdx pushfq pushq $__KERNEL_CS - pushq $repeat_nmi + leaqrepeat_nmi(%rip), %rdx + pushq %rdx /* Put stack back */ addq$(6*8), %rsp @@ -1577,7 +1579,11 @@ first_nmi: addq$8, (%rsp) /* Fix up RSP */ pushfq /* RFLAGS */ pushq $__KERNEL_CS/* CS */ - pushq $1f /* RIP */ + pushq $0 /* Futur return address */ + pushq %rax/* Save RAX */ + leaq1f(%rip), %rax /* RIP */ + movq%rax, 8(%rsp) /* Put 1f on return address */ + popq%rax/* Restore RAX */ iretq /* continues at repeat_nmi below */ UNWIND_HINT_IRET_REGS 1: diff --git a/arch/x86/kernel/relocate_kernel_64.S b/arch/x86/kernel/relocate_kernel_64.S index a7227dfe1a2b..0c0fc259a4e2 100644 --- a/arch/x86/kernel/relocate_kernel_64.S +++ b/arch/x86/kernel/relocate_kernel_64.S @@ -208,11 +208,9 @@ identity_mapped: movq%rax, %cr3 lea PAGE_SIZE(%r8), %rsp callswap_pages - jmp *virtual_mapped_addr(%rip) - - /* Absolute value for PIE support */ -virtual_mapped_addr: - .quad virtual_mapped + movabsq $virtual_mapped, %rax + pushq %rax + ret virtual_mapped: movqRSP(%r8), %rsp -- 2.17.0.921.gf22659ad46-goog
