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https://abf.rosa.ru/djam/kernel-6.6.git
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134 lines
4.3 KiB
Diff
134 lines
4.3 KiB
Diff
From bd997a1e8e262706b5a65cb1ff48f939c698b835 Mon Sep 17 00:00:00 2001
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From: Alexey Sheplyakov <asheplyakov@basealt.ru>
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Date: Mon, 23 May 2022 19:28:24 +0400
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Subject: [PATCH 607/631] arm64-stub: fixed secondary cores boot on Baikal-M
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SoC
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Old versions of Baikal-M firmware (ARM-TF) deny execution attempts
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outside of the (physical) address ranges
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[0x80000000, 0x8FFFFFFF] and [0xA0000000, 0xBFFFFFFF]
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Thus PSCI calls to boot secondary cores fail unless the kernel image
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resides in one of these address ranges. However UEFI PE/COFF loader
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puts the kernel image into the forbidden range. Since the alignment
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is good enough EFI stub does not try to relocate the kernel.
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As a result secondary CPUs fail to boot.
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Relocation to a random address is not going to work either.
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Therefore automatically disable kaslr on "known bad" systems (for
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now only Baikal-M) and forcibly relocate the kernel to a low(er)
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address.
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This patch is necessary only for old firmware (pre SDK-M 5.1) and
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prevents kalsr from working on Baikal-M systems.
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Signed-off-by: Alexey Sheplyakov <asheplyakov@basealt.ru>
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X-DONTUPSTREAM
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X-legacy
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X-feature-Baikal-M
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[ Adapted for kernel 6.6 ]
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Signed-off-by: Mikhail Novosyolov <m.novosyolov@rosalinux.ru>
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---
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drivers/firmware/efi/libstub/kaslr.c | 61 +++++++++++++++++++++++++++-
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1 file changed, 60 insertions(+), 1 deletion(-)
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diff --git a/drivers/firmware/efi/libstub/kaslr.c b/drivers/firmware/efi/libstub/kaslr.c
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index 1a9808012abd..bbbf496853cd 100644
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--- a/drivers/firmware/efi/libstub/kaslr.c
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+++ b/drivers/firmware/efi/libstub/kaslr.c
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@@ -4,9 +4,47 @@
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* architectures to deal with physical address space randomization.
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*/
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#include <linux/efi.h>
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+#include <linux/libfdt.h>
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#include "efistub.h"
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+static inline efi_status_t efi_low_alloc(unsigned long size, unsigned long align,
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+ unsigned long *addr)
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+{
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+ /*
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+ * Don't allocate at 0x0. It will confuse code that
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+ * checks pointers against NULL. Skip the first 8
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+ * bytes so we start at a nice even number.
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+ */
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+ return efi_low_alloc_above(size, align, addr, 0x8);
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+}
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+
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+static const char* machines_need_low_alloc[] = {
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+ "baikal,baikal-m",
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+ "baikal,bm1000",
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+};
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+
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+static bool need_low_alloc(void) {
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+ size_t i;
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+ const void *fdt;
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+ const char *match;
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+
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+ fdt = get_efi_config_table(DEVICE_TREE_GUID);
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+ if (!fdt) {
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+ efi_info("failed to retrive FDT from EFI\n");
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+ return false;
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+ }
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+
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+ for (i = 0; i < ARRAY_SIZE(machines_need_low_alloc); i++) {
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+ match = machines_need_low_alloc[i];
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+ if (fdt_node_check_compatible(fdt, 0, match) == 0) {
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+ efi_info("machine %s: forcing kernel relocation to low address\n", match);
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+ return true;
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+ }
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+ }
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+ return false;
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+}
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+
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/**
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* efi_kaslr_get_phys_seed() - Get random seed for physical kernel KASLR
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* @image_handle: Handle to the image
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@@ -26,8 +64,17 @@ u32 efi_kaslr_get_phys_seed(efi_handle_t image_handle)
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if (!IS_ENABLED(CONFIG_RANDOMIZE_BASE))
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return 0;
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+ bool force_low_reloc = need_low_alloc();
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+ if (force_low_reloc) {
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+ if (!efi_nokaslr) {
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+ efi_info("booting on a broken firmware, KASLR will be disabled\n");
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+ efi_nokaslr = true;
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+ }
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+ }
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+
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if (efi_nokaslr) {
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- efi_info("KASLR disabled on kernel command line\n");
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+ if (!force_low_reloc)
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+ efi_info("KASLR disabled on kernel command line\n");
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} else if (efi_bs_call(handle_protocol, image_handle,
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&li_fixed_proto, &p) == EFI_SUCCESS) {
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efi_info("Image placement fixed by loader\n");
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@@ -126,6 +173,15 @@ efi_status_t efi_kaslr_relocate_kernel(unsigned long *image_addr,
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status = EFI_OUT_OF_RESOURCES;
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}
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+ if (force_low_reloc) {
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+ status = efi_low_alloc(*reserve_size,
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+ min_kimg_align,
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+ reserve_addr);
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+ if (status != EFI_SUCCESS) {
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+ efi_err("Failed to relocate kernel, expect secondary CPUs boot failure\n");
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+ }
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+ }
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+
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if (status != EFI_SUCCESS) {
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if (!check_image_region(*image_addr, kernel_memsize)) {
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efi_err("FIRMWARE BUG: Image BSS overlaps adjacent EFI memory region\n");
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@@ -152,6 +208,9 @@ efi_status_t efi_kaslr_relocate_kernel(unsigned long *image_addr,
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memcpy((void *)*reserve_addr, (void *)*image_addr, kernel_size);
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*image_addr = *reserve_addr;
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+ if (efi_nokaslr) {
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+ efi_info("relocating kernel to 0x%lx\n", *image_addr);
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+ }
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efi_icache_sync(*image_addr, *image_addr + kernel_codesize);
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efi_remap_image(*image_addr, *reserve_size, kernel_codesize);
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--
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2.40.1
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