From 9999e48639b3cecb08ffb37358bcba3b48161b29 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Fri, 10 May 2024 08:50:17 +0000
Subject: [PATCH] add ax88772_rst

---
 kernel/arch/x86/platform/efi/quirks.c |  178 ++++++++++++++++++++++++++++++++++++++++++++++-------------
 1 files changed, 138 insertions(+), 40 deletions(-)

diff --git a/kernel/arch/x86/platform/efi/quirks.c b/kernel/arch/x86/platform/efi/quirks.c
index 006eb09..c1eec01 100644
--- a/kernel/arch/x86/platform/efi/quirks.c
+++ b/kernel/arch/x86/platform/efi/quirks.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 #define pr_fmt(fmt) "efi: " fmt
 
 #include <linux/init.h>
@@ -8,7 +9,6 @@
 #include <linux/efi.h>
 #include <linux/slab.h>
 #include <linux/memblock.h>
-#include <linux/bootmem.h>
 #include <linux/acpi.h>
 #include <linux/dmi.h>
 
@@ -16,6 +16,8 @@
 #include <asm/efi.h>
 #include <asm/uv/uv.h>
 #include <asm/cpu_device_id.h>
+#include <asm/realmode.h>
+#include <asm/reboot.h>
 
 #define EFI_MIN_RESERVE 5120
 
@@ -242,7 +244,7 @@
  */
 void __init efi_arch_mem_reserve(phys_addr_t addr, u64 size)
 {
-	phys_addr_t new_phys, new_size;
+	struct efi_memory_map_data data = { 0 };
 	struct efi_mem_range mr;
 	efi_memory_desc_t md;
 	int num_entries;
@@ -270,15 +272,12 @@
 	num_entries = efi_memmap_split_count(&md, &mr.range);
 	num_entries += efi.memmap.nr_map;
 
-	new_size = efi.memmap.desc_size * num_entries;
-
-	new_phys = efi_memmap_alloc(num_entries);
-	if (!new_phys) {
+	if (efi_memmap_alloc(num_entries, &data) != 0) {
 		pr_err("Could not allocate boot services memmap\n");
 		return;
 	}
 
-	new = early_memremap_prot(new_phys, new_size,
+	new = early_memremap_prot(data.phys_map, data.size,
 				  pgprot_val(pgprot_encrypted(FIXMAP_PAGE_NORMAL)));
 	if (!new) {
 		pr_err("Failed to map new boot services memmap\n");
@@ -286,9 +285,9 @@
 	}
 
 	efi_memmap_insert(&efi.memmap, new, &mr);
-	early_memunmap(new, new_size);
+	early_memunmap(new, data.size);
 
-	efi_memmap_install(new_phys, num_entries);
+	efi_memmap_install(&data);
 	e820__range_update(addr, size, E820_TYPE_RAM, E820_TYPE_RESERVED);
 	e820__update_table(e820_table);
 }
@@ -303,7 +302,7 @@
  * - Not within any part of the kernel
  * - Not the BIOS reserved area (E820_TYPE_RESERVED, E820_TYPE_NVS, etc)
  */
-static bool can_free_region(u64 start, u64 size)
+static __init bool can_free_region(u64 start, u64 size)
 {
 	if (start + size > __pa_symbol(_text) && start <= __pa_symbol(_end))
 		return false;
@@ -318,6 +317,9 @@
 {
 	efi_memory_desc_t *md;
 
+	if (!efi_enabled(EFI_MEMMAP))
+		return;
+
 	for_each_efi_memory_desc(md) {
 		u64 start = md->phys_addr;
 		u64 size = md->num_pages << EFI_PAGE_SHIFT;
@@ -331,7 +333,7 @@
 
 		/*
 		 * Because the following memblock_reserve() is paired
-		 * with free_bootmem_late() for this region in
+		 * with memblock_free_late() for this region in
 		 * efi_free_boot_services(), we must be extremely
 		 * careful not to reserve, and subsequently free,
 		 * critical regions of memory (like the kernel image) or
@@ -362,18 +364,48 @@
 		 * doesn't make sense as far as the firmware is
 		 * concerned, but it does provide us with a way to tag
 		 * those regions that must not be paired with
-		 * free_bootmem_late().
+		 * memblock_free_late().
 		 */
 		md->attribute |= EFI_MEMORY_RUNTIME;
 	}
 }
 
+/*
+ * Apart from having VA mappings for EFI boot services code/data regions,
+ * (duplicate) 1:1 mappings were also created as a quirk for buggy firmware. So,
+ * unmap both 1:1 and VA mappings.
+ */
+static void __init efi_unmap_pages(efi_memory_desc_t *md)
+{
+	pgd_t *pgd = efi_mm.pgd;
+	u64 pa = md->phys_addr;
+	u64 va = md->virt_addr;
+
+	/*
+	 * EFI mixed mode has all RAM mapped to access arguments while making
+	 * EFI runtime calls, hence don't unmap EFI boot services code/data
+	 * regions.
+	 */
+	if (efi_is_mixed())
+		return;
+
+	if (kernel_unmap_pages_in_pgd(pgd, pa, md->num_pages))
+		pr_err("Failed to unmap 1:1 mapping for 0x%llx\n", pa);
+
+	if (kernel_unmap_pages_in_pgd(pgd, va, md->num_pages))
+		pr_err("Failed to unmap VA mapping for 0x%llx\n", va);
+}
+
 void __init efi_free_boot_services(void)
 {
-	phys_addr_t new_phys, new_size;
+	struct efi_memory_map_data data = { 0 };
 	efi_memory_desc_t *md;
 	int num_entries = 0;
 	void *new, *new_md;
+
+	/* Keep all regions for /sys/kernel/debug/efi */
+	if (efi_enabled(EFI_DBG))
+		return;
 
 	for_each_efi_memory_desc(md) {
 		unsigned long long start = md->phys_addr;
@@ -393,6 +425,13 @@
 		}
 
 		/*
+		 * Before calling set_virtual_address_map(), EFI boot services
+		 * code/data regions were mapped as a quirk for buggy firmware.
+		 * Unmap them from efi_pgd before freeing them up.
+		 */
+		efi_unmap_pages(md);
+
+		/*
 		 * Nasty quirk: if all sub-1MB memory is used for boot
 		 * services, we can get here without having allocated the
 		 * real mode trampoline.  It's too late to hand boot services
@@ -407,25 +446,23 @@
 		 */
 		rm_size = real_mode_size_needed();
 		if (rm_size && (start + rm_size) < (1<<20) && size >= rm_size) {
-			set_real_mode_mem(start, rm_size);
+			set_real_mode_mem(start);
 			start += rm_size;
 			size -= rm_size;
 		}
 
-		free_bootmem_late(start, size);
+		memblock_free_late(start, size);
 	}
 
 	if (!num_entries)
 		return;
 
-	new_size = efi.memmap.desc_size * num_entries;
-	new_phys = efi_memmap_alloc(num_entries);
-	if (!new_phys) {
+	if (efi_memmap_alloc(num_entries, &data) != 0) {
 		pr_err("Failed to allocate new EFI memmap\n");
 		return;
 	}
 
-	new = memremap(new_phys, new_size, MEMREMAP_WB);
+	new = memremap(data.phys_map, data.size, MEMREMAP_WB);
 	if (!new) {
 		pr_err("Failed to map new EFI memmap\n");
 		return;
@@ -449,7 +486,7 @@
 
 	memunmap(new);
 
-	if (efi_memmap_install(new_phys, num_entries)) {
+	if (efi_memmap_install(&data) != 0) {
 		pr_err("Could not install new EFI memmap\n");
 		return;
 	}
@@ -469,6 +506,9 @@
 	int i, sz, ret = 0;
 	void *p, *tablep;
 	struct efi_setup_data *data;
+
+	if (nr_tables == 0)
+		return 0;
 
 	if (!efi_setup)
 		return 0;
@@ -494,7 +534,7 @@
 		goto out_memremap;
 	}
 
-	for (i = 0; i < efi.systab->nr_tables; i++) {
+	for (i = 0; i < nr_tables; i++) {
 		efi_guid_t guid;
 
 		guid = ((efi_config_table_64_t *)p)->guid;
@@ -511,16 +551,6 @@
 	return ret;
 }
 
-static const struct dmi_system_id sgi_uv1_dmi[] = {
-	{ NULL, "SGI UV1",
-		{	DMI_MATCH(DMI_PRODUCT_NAME,	"Stoutland Platform"),
-			DMI_MATCH(DMI_PRODUCT_VERSION,	"1.0"),
-			DMI_MATCH(DMI_BIOS_VENDOR,	"SGI.COM"),
-		}
-	},
-	{ } /* NULL entry stops DMI scanning */
-};
-
 void __init efi_apply_memmap_quirks(void)
 {
 	/*
@@ -532,10 +562,6 @@
 		pr_info("Setup done, disabling due to 32/64-bit mismatch\n");
 		efi_memmap_unmap();
 	}
-
-	/* UV2+ BIOS has a fix for this issue.  UV1 still needs the quirk. */
-	if (dmi_check_system(sgi_uv1_dmi))
-		set_bit(EFI_OLD_MEMMAP, &efi.flags);
 }
 
 /*
@@ -609,12 +635,9 @@
 	return 1;
 }
 
-#define ICPU(family, model, quirk_handler) \
-	{ X86_VENDOR_INTEL, family, model, X86_FEATURE_ANY, \
-	  (unsigned long)&quirk_handler }
-
 static const struct x86_cpu_id efi_capsule_quirk_ids[] = {
-	ICPU(5, 9, qrk_capsule_setup_info),	/* Intel Quark X1000 */
+	X86_MATCH_VENDOR_FAM_MODEL(INTEL, 5, INTEL_FAM5_QUARK_X1000,
+				   &qrk_capsule_setup_info),
 	{ }
 };
 
@@ -653,3 +676,78 @@
 }
 
 #endif
+
+/*
+ * If any access by any efi runtime service causes a page fault, then,
+ * 1. If it's efi_reset_system(), reboot through BIOS.
+ * 2. If any other efi runtime service, then
+ *    a. Return error status to the efi caller process.
+ *    b. Disable EFI Runtime Services forever and
+ *    c. Freeze efi_rts_wq and schedule new process.
+ *
+ * @return: Returns, if the page fault is not handled. This function
+ * will never return if the page fault is handled successfully.
+ */
+void efi_recover_from_page_fault(unsigned long phys_addr)
+{
+	if (!IS_ENABLED(CONFIG_X86_64))
+		return;
+
+	/*
+	 * Make sure that an efi runtime service caused the page fault.
+	 */
+	if (efi_rts_work.efi_rts_id == EFI_NONE)
+		return;
+
+	/*
+	 * Address range 0x0000 - 0x0fff is always mapped in the efi_pgd, so
+	 * page faulting on these addresses isn't expected.
+	 */
+	if (phys_addr <= 0x0fff)
+		return;
+
+	/*
+	 * Print stack trace as it might be useful to know which EFI Runtime
+	 * Service is buggy.
+	 */
+	WARN(1, FW_BUG "Page fault caused by firmware at PA: 0x%lx\n",
+	     phys_addr);
+
+	/*
+	 * Buggy efi_reset_system() is handled differently from other EFI
+	 * Runtime Services as it doesn't use efi_rts_wq. Although,
+	 * native_machine_emergency_restart() says that machine_real_restart()
+	 * could fail, it's better not to compilcate this fault handler
+	 * because this case occurs *very* rarely and hence could be improved
+	 * on a need by basis.
+	 */
+	if (efi_rts_work.efi_rts_id == EFI_RESET_SYSTEM) {
+		pr_info("efi_reset_system() buggy! Reboot through BIOS\n");
+		machine_real_restart(MRR_BIOS);
+		return;
+	}
+
+	/*
+	 * Before calling EFI Runtime Service, the kernel has switched the
+	 * calling process to efi_mm. Hence, switch back to task_mm.
+	 */
+	arch_efi_call_virt_teardown();
+
+	/* Signal error status to the efi caller process */
+	efi_rts_work.status = EFI_ABORTED;
+	complete(&efi_rts_work.efi_rts_comp);
+
+	clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
+	pr_info("Froze efi_rts_wq and disabled EFI Runtime Services\n");
+
+	/*
+	 * Call schedule() in an infinite loop, so that any spurious wake ups
+	 * will never run efi_rts_wq again.
+	 */
+	for (;;) {
+		set_current_state(TASK_IDLE);
+		schedule();
+	}
+
+	return;
+}

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