The BSS_DECRYPT section that gets emitted into .bss will be empty if CONFIG_AMD_MEM_ENCRYPT is not defined. However, due to the fact that it is injected into .bss rather than emitted as a separate section, the 2 MiB alignment that it specifies is still taken into account unconditionally, pushing .bss out to the next 2 MiB boundary, leaving a gap that is never freed.
So only emit a non-empty BSS_DECRYPT section if it is going to be used. In that case, it would still be nice to free the padding, but that is left for later. Signed-off-by: Ard Biesheuvel <[email protected]> --- arch/x86/kernel/vmlinux.lds.S | 21 +++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index d7af4a64c211..3a24a3fc55f5 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -67,7 +67,18 @@ const_cpu_current_top_of_stack = cpu_current_top_of_stack; #define ALIGN_ENTRY_TEXT_BEGIN . = ALIGN(PMD_SIZE); #define ALIGN_ENTRY_TEXT_END . = ALIGN(PMD_SIZE); +#else + +#define X86_ALIGN_RODATA_BEGIN +#define X86_ALIGN_RODATA_END \ + . = ALIGN(PAGE_SIZE); \ + __end_rodata_aligned = .; +#define ALIGN_ENTRY_TEXT_BEGIN +#define ALIGN_ENTRY_TEXT_END +#endif + +#ifdef CONFIG_AMD_MEM_ENCRYPT /* * This section contains data which will be mapped as decrypted. Memory * encryption operates on a page basis. Make this section PMD-aligned @@ -88,17 +99,9 @@ const_cpu_current_top_of_stack = cpu_current_top_of_stack; __pi___end_bss_decrypted = .; \ #else - -#define X86_ALIGN_RODATA_BEGIN -#define X86_ALIGN_RODATA_END \ - . = ALIGN(PAGE_SIZE); \ - __end_rodata_aligned = .; - -#define ALIGN_ENTRY_TEXT_BEGIN -#define ALIGN_ENTRY_TEXT_END #define BSS_DECRYPTED - #endif + #if defined(CONFIG_X86_64) && defined(CONFIG_KEXEC_CORE) #define KEXEC_RELOCATE_KERNEL \ . = ALIGN(0x100); \ -- 2.47.3
