diff options
Diffstat (limited to 'arch/x86/kernel/machine_kexec_64.c')
| -rw-r--r-- | arch/x86/kernel/machine_kexec_64.c | 44 |
1 files changed, 35 insertions, 9 deletions
diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c index 697fb99406e6..15088d14904f 100644 --- a/arch/x86/kernel/machine_kexec_64.c +++ b/arch/x86/kernel/machine_kexec_64.c @@ -29,6 +29,7 @@ #include <asm/set_memory.h> #include <asm/cpu.h> #include <asm/efi.h> +#include <asm/processor.h> #ifdef CONFIG_ACPI /* @@ -346,6 +347,22 @@ int machine_kexec_prepare(struct kimage *image) unsigned long reloc_end = (unsigned long)__relocate_kernel_end; int result; + /* + * Some early TDX-capable platforms have an erratum. A kernel + * partial write (a write transaction of less than cacheline + * lands at memory controller) to TDX private memory poisons that + * memory, and a subsequent read triggers a machine check. + * + * On those platforms the old kernel must reset TDX private + * memory before jumping to the new kernel otherwise the new + * kernel may see unexpected machine check. For simplicity + * just fail kexec/kdump on those platforms. + */ + if (boot_cpu_has_bug(X86_BUG_TDX_PW_MCE)) { + pr_info_once("Not allowed on platform with tdx_pw_mce bug\n"); + return -EOPNOTSUPP; + } + /* Setup the identity mapped 64bit page table */ result = init_pgtable(image, __pa(control_page)); if (result) @@ -384,16 +401,10 @@ void __nocfi machine_kexec(struct kimage *image) { unsigned long reloc_start = (unsigned long)__relocate_kernel_start; relocate_kernel_fn *relocate_kernel_ptr; - unsigned int host_mem_enc_active; + unsigned int relocate_kernel_flags; int save_ftrace_enabled; void *control_page; - /* - * This must be done before load_segments() since if call depth tracking - * is used then GS must be valid to make any function calls. - */ - host_mem_enc_active = cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT); - #ifdef CONFIG_KEXEC_JUMP if (image->preserve_context) save_processor_state(); @@ -427,6 +438,17 @@ void __nocfi machine_kexec(struct kimage *image) */ relocate_kernel_ptr = control_page + (unsigned long)relocate_kernel - reloc_start; + relocate_kernel_flags = 0; + if (image->preserve_context) + relocate_kernel_flags |= RELOC_KERNEL_PRESERVE_CONTEXT; + + /* + * This must be done before load_segments() since it resets + * GS to 0 and percpu data needs the correct GS to work. + */ + if (this_cpu_read(cache_state_incoherent)) + relocate_kernel_flags |= RELOC_KERNEL_CACHE_INCOHERENT; + /* * The segment registers are funny things, they have both a * visible and an invisible part. Whenever the visible part is @@ -436,6 +458,11 @@ void __nocfi machine_kexec(struct kimage *image) * * Take advantage of this here by force loading the segments, * before the GDT is zapped with an invalid value. + * + * load_segments() resets GS to 0. Don't make any function call + * after here since call depth tracking uses percpu variables to + * operate (relocate_kernel() is explicitly ignored by call depth + * tracking). */ load_segments(); @@ -443,8 +470,7 @@ void __nocfi machine_kexec(struct kimage *image) image->start = relocate_kernel_ptr((unsigned long)image->head, virt_to_phys(control_page), image->start, - image->preserve_context, - host_mem_enc_active); + relocate_kernel_flags); #ifdef CONFIG_KEXEC_JUMP if (image->preserve_context) |