diff options
Diffstat (limited to 'arch/x86/boot/compressed')
| -rw-r--r-- | arch/x86/boot/compressed/Makefile | 3 | ||||
| -rw-r--r-- | arch/x86/boot/compressed/head_64.S | 32 | ||||
| -rw-r--r-- | arch/x86/boot/compressed/kaslr.c | 5 | ||||
| -rw-r--r-- | arch/x86/boot/compressed/mem_encrypt.S | 120 | ||||
| -rw-r--r-- | arch/x86/boot/compressed/misc.c | 16 | ||||
| -rw-r--r-- | arch/x86/boot/compressed/misc.h | 2 | ||||
| -rw-r--r-- | arch/x86/boot/compressed/pagetable.c | 8 | ||||
| -rw-r--r-- | arch/x86/boot/compressed/pgtable_64.c | 28 |
8 files changed, 204 insertions, 10 deletions
diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index 4b7575b00563..f25e1530e064 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -36,6 +36,7 @@ KBUILD_CFLAGS += -mno-mmx -mno-sse KBUILD_CFLAGS += $(call cc-option,-ffreestanding) KBUILD_CFLAGS += $(call cc-option,-fno-stack-protector) KBUILD_CFLAGS += $(call cc-disable-warning, address-of-packed-member) +KBUILD_CFLAGS += $(call cc-disable-warning, gnu) KBUILD_AFLAGS := $(KBUILD_CFLAGS) -D__ASSEMBLY__ GCOV_PROFILE := n @@ -78,6 +79,8 @@ vmlinux-objs-$(CONFIG_EARLY_PRINTK) += $(obj)/early_serial_console.o vmlinux-objs-$(CONFIG_RANDOMIZE_BASE) += $(obj)/kaslr.o ifdef CONFIG_X86_64 vmlinux-objs-$(CONFIG_RANDOMIZE_BASE) += $(obj)/pagetable.o + vmlinux-objs-y += $(obj)/mem_encrypt.o + vmlinux-objs-y += $(obj)/pgtable_64.o endif $(obj)/eboot.o: KBUILD_CFLAGS += -fshort-wchar -mno-red-zone diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index beb255b66447..fc313e29fe2c 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -131,6 +131,19 @@ ENTRY(startup_32) /* * Build early 4G boot pagetable */ + /* + * If SEV is active then set the encryption mask in the page tables. + * This will insure that when the kernel is copied and decompressed + * it will be done so encrypted. + */ + call get_sev_encryption_bit + xorl %edx, %edx + testl %eax, %eax + jz 1f + subl $32, %eax /* Encryption bit is always above bit 31 */ + bts %eax, %edx /* Set encryption mask for page tables */ +1: + /* Initialize Page tables to 0 */ leal pgtable(%ebx), %edi xorl %eax, %eax @@ -141,12 +154,14 @@ ENTRY(startup_32) leal pgtable + 0(%ebx), %edi leal 0x1007 (%edi), %eax movl %eax, 0(%edi) + addl %edx, 4(%edi) /* Build Level 3 */ leal pgtable + 0x1000(%ebx), %edi leal 0x1007(%edi), %eax movl $4, %ecx 1: movl %eax, 0x00(%edi) + addl %edx, 0x04(%edi) addl $0x00001000, %eax addl $8, %edi decl %ecx @@ -157,6 +172,7 @@ ENTRY(startup_32) movl $0x00000183, %eax movl $2048, %ecx 1: movl %eax, 0(%edi) + addl %edx, 4(%edi) addl $0x00200000, %eax addl $8, %edi decl %ecx @@ -289,10 +305,18 @@ ENTRY(startup_64) leaq boot_stack_end(%rbx), %rsp #ifdef CONFIG_X86_5LEVEL - /* Check if 5-level paging has already enabled */ - movq %cr4, %rax - testl $X86_CR4_LA57, %eax - jnz lvl5 + /* + * Check if we need to enable 5-level paging. + * RSI holds real mode data and need to be preserved across + * a function call. + */ + pushq %rsi + call l5_paging_required + popq %rsi + + /* If l5_paging_required() returned zero, we're done here. */ + cmpq $0, %rax + je lvl5 /* * At this point we are in long mode with 4-level paging enabled, diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c index a63fbc25ce84..8199a6187251 100644 --- a/arch/x86/boot/compressed/kaslr.c +++ b/arch/x86/boot/compressed/kaslr.c @@ -171,7 +171,6 @@ parse_memmap(char *p, unsigned long long *start, unsigned long long *size) static void mem_avoid_memmap(char *str) { static int i; - int rc; if (i >= MAX_MEMMAP_REGIONS) return; @@ -219,7 +218,7 @@ static int handle_mem_memmap(void) return 0; tmp_cmdline = malloc(len + 1); - if (!tmp_cmdline ) + if (!tmp_cmdline) error("Failed to allocate space for tmp_cmdline"); memcpy(tmp_cmdline, args, len); @@ -363,7 +362,7 @@ static void mem_avoid_init(unsigned long input, unsigned long input_size, cmd_line |= boot_params->hdr.cmd_line_ptr; /* Calculate size of cmd_line. */ ptr = (char *)(unsigned long)cmd_line; - for (cmd_line_size = 0; ptr[cmd_line_size++]; ) + for (cmd_line_size = 0; ptr[cmd_line_size++];) ; mem_avoid[MEM_AVOID_CMDLINE].start = cmd_line; mem_avoid[MEM_AVOID_CMDLINE].size = cmd_line_size; diff --git a/arch/x86/boot/compressed/mem_encrypt.S b/arch/x86/boot/compressed/mem_encrypt.S new file mode 100644 index 000000000000..54f5f6625a73 --- /dev/null +++ b/arch/x86/boot/compressed/mem_encrypt.S @@ -0,0 +1,120 @@ +/* + * AMD Memory Encryption Support + * + * Copyright (C) 2017 Advanced Micro Devices, Inc. + * + * Author: Tom Lendacky <thomas.lendacky@amd.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/linkage.h> + +#include <asm/processor-flags.h> +#include <asm/msr.h> +#include <asm/asm-offsets.h> + + .text + .code32 +ENTRY(get_sev_encryption_bit) + xor %eax, %eax + +#ifdef CONFIG_AMD_MEM_ENCRYPT + push %ebx + push %ecx + push %edx + push %edi + + /* + * RIP-relative addressing is needed to access the encryption bit + * variable. Since we are running in 32-bit mode we need this call/pop + * sequence to get the proper relative addressing. + */ + call 1f +1: popl %edi + subl $1b, %edi + + movl enc_bit(%edi), %eax + cmpl $0, %eax + jge .Lsev_exit + + /* Check if running under a hypervisor */ + movl $1, %eax + cpuid + bt $31, %ecx /* Check the hypervisor bit */ + jnc .Lno_sev + + movl $0x80000000, %eax /* CPUID to check the highest leaf */ + cpuid + cmpl $0x8000001f, %eax /* See if 0x8000001f is available */ + jb .Lno_sev + + /* + * Check for the SEV feature: + * CPUID Fn8000_001F[EAX] - Bit 1 + * CPUID Fn8000_001F[EBX] - Bits 5:0 + * Pagetable bit position used to indicate encryption + */ + movl $0x8000001f, %eax + cpuid + bt $1, %eax /* Check if SEV is available */ + jnc .Lno_sev + + movl $MSR_AMD64_SEV, %ecx /* Read the SEV MSR */ + rdmsr + bt $MSR_AMD64_SEV_ENABLED_BIT, %eax /* Check if SEV is active */ + jnc .Lno_sev + + movl %ebx, %eax + andl $0x3f, %eax /* Return the encryption bit location */ + movl %eax, enc_bit(%edi) + jmp .Lsev_exit + +.Lno_sev: + xor %eax, %eax + movl %eax, enc_bit(%edi) + +.Lsev_exit: + pop %edi + pop %edx + pop %ecx + pop %ebx + +#endif /* CONFIG_AMD_MEM_ENCRYPT */ + + ret +ENDPROC(get_sev_encryption_bit) + + .code64 +ENTRY(get_sev_encryption_mask) + xor %rax, %rax + +#ifdef CONFIG_AMD_MEM_ENCRYPT + push %rbp + push %rdx + + movq %rsp, %rbp /* Save current stack pointer */ + + call get_sev_encryption_bit /* Get the encryption bit position */ + testl %eax, %eax + jz .Lno_sev_mask + + xor %rdx, %rdx + bts %rax, %rdx /* Create the encryption mask */ + mov %rdx, %rax /* ... and return it */ + +.Lno_sev_mask: + movq %rbp, %rsp /* Restore original stack pointer */ + + pop %rdx + pop %rbp +#endif + + ret +ENDPROC(get_sev_encryption_mask) + + .data +enc_bit: + .int 0xffffffff diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c index b50c42455e25..98761a1576ce 100644 --- a/arch/x86/boot/compressed/misc.c +++ b/arch/x86/boot/compressed/misc.c @@ -169,6 +169,16 @@ void __puthex(unsigned long value) } } +static bool l5_supported(void) +{ + /* Check if leaf 7 is supported. */ + if (native_cpuid_eax(0) < 7) + return 0; + + /* Check if la57 is supported. */ + return native_cpuid_ecx(7) & (1 << (X86_FEATURE_LA57 & 31)); +} + #if CONFIG_X86_NEED_RELOCS static void handle_relocations(void *output, unsigned long output_len, unsigned long virt_addr) @@ -362,6 +372,12 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap, console_init(); debug_putstr("early console in extract_kernel\n"); + if (IS_ENABLED(CONFIG_X86_5LEVEL) && !l5_supported()) { + error("This linux kernel as configured requires 5-level paging\n" + "This CPU does not support the required 'cr4.la57' feature\n" + "Unable to boot - please use a kernel appropriate for your CPU\n"); + } + free_mem_ptr = heap; /* Heap */ free_mem_end_ptr = heap + BOOT_HEAP_SIZE; diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h index 32d4ec2e0243..9d323dc6b159 100644 --- a/arch/x86/boot/compressed/misc.h +++ b/arch/x86/boot/compressed/misc.h @@ -109,4 +109,6 @@ static inline void console_init(void) { } #endif +unsigned long get_sev_encryption_mask(void); + #endif diff --git a/arch/x86/boot/compressed/pagetable.c b/arch/x86/boot/compressed/pagetable.c index e691ff734cb5..b5e5e02f8cde 100644 --- a/arch/x86/boot/compressed/pagetable.c +++ b/arch/x86/boot/compressed/pagetable.c @@ -80,16 +80,18 @@ static unsigned long top_level_pgt; * Mapping information structure passed to kernel_ident_mapping_init(). * Due to relocation, pointers must be assigned at run time not build time. */ -static struct x86_mapping_info mapping_info = { - .page_flag = __PAGE_KERNEL_LARGE_EXEC, -}; +static struct x86_mapping_info mapping_info; /* Locates and clears a region for a new top level page table. */ void initialize_identity_maps(void) { + unsigned long sev_me_mask = get_sev_encryption_mask(); + /* Init mapping_info with run-time function/buffer pointers. */ mapping_info.alloc_pgt_page = alloc_pgt_page; mapping_info.context = &pgt_data; + mapping_info.page_flag = __PAGE_KERNEL_LARGE_EXEC | sev_me_mask; + mapping_info.kernpg_flag = _KERNPG_TABLE | sev_me_mask; /* * It should be impossible for this not to already be true, diff --git a/arch/x86/boot/compressed/pgtable_64.c b/arch/x86/boot/compressed/pgtable_64.c new file mode 100644 index 000000000000..b4469a37e9a1 --- /dev/null +++ b/arch/x86/boot/compressed/pgtable_64.c @@ -0,0 +1,28 @@ +#include <asm/processor.h> + +/* + * __force_order is used by special_insns.h asm code to force instruction + * serialization. + * + * It is not referenced from the code, but GCC < 5 with -fPIE would fail + * due to an undefined symbol. Define it to make these ancient GCCs work. + */ +unsigned long __force_order; + +int l5_paging_required(void) +{ + /* Check if leaf 7 is supported. */ + + if (native_cpuid_eax(0) < 7) + return 0; + + /* Check if la57 is supported. */ + if (!(native_cpuid_ecx(7) & (1 << (X86_FEATURE_LA57 & 31)))) + return 0; + + /* Check if 5-level paging has already been enabled. */ + if (native_read_cr4() & X86_CR4_LA57) + return 0; + + return 1; +} |