From f7e7ce93aac13118281bcef8407b5df1a6b16822 Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Wed, 11 Aug 2021 10:51:01 +0200 Subject: of: fdt: Add generic support for handling elf core headers property There are two methods to specify the location of the elf core headers: using the "elfcorehdr=" kernel parameter, as handled by generic code in kernel/crash_dump.c, or using the "linux,elfcorehdr" property under the "/chosen" node in the Device Tree, as handled by architecture-specific code in arch/arm64/mm/init.c. Extend support for "linux,elfcorehdr" to all platforms supporting DT by adding platform-agnostic handling for handling this property to the FDT core code. This can co-exist safely with the architecture-specific handling, until the latter has been removed. This requires moving the call to of_scan_flat_dt() up, as the code scanning the "/chosen" node now needs to be aware of the values of "#address-cells" and "#size-cells". Signed-off-by: Geert Uytterhoeven Signed-off-by: Rob Herring Link: https://lore.kernel.org/r/c7e46e50aaf87ef49bdaa61358d25b122f32b7df.1628670468.git.geert+renesas@glider.be --- drivers/of/fdt.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 56 insertions(+), 3 deletions(-) (limited to 'drivers/of') diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c index 09ed7e597eee..a421c90c83fb 100644 --- a/drivers/of/fdt.c +++ b/drivers/of/fdt.c @@ -8,6 +8,7 @@ #define pr_fmt(fmt) "OF: fdt: " fmt +#include #include #include #include @@ -597,6 +598,30 @@ static int __init __fdt_scan_reserved_mem(unsigned long node, const char *uname, return 0; } +/* + * reserve_elfcorehdr() - reserves memory for elf core header + * + * This function reserves the memory occupied by an elf core header + * described in the device tree. This region contains all the + * information about primary kernel's core image and is used by a dump + * capture kernel to access the system memory on primary kernel. + */ +static void __init reserve_elfcorehdr(void) +{ + if (!IS_ENABLED(CONFIG_CRASH_DUMP) || !elfcorehdr_size) + return; + + if (memblock_is_region_reserved(elfcorehdr_addr, elfcorehdr_size)) { + pr_warn("elfcorehdr is overlapped\n"); + return; + } + + memblock_reserve(elfcorehdr_addr, elfcorehdr_size); + + pr_info("Reserving %llu KiB of memory at 0x%llx for elfcorehdr\n", + elfcorehdr_size >> 10, elfcorehdr_addr); +} + /** * early_init_fdt_scan_reserved_mem() - create reserved memory regions * @@ -622,6 +647,7 @@ void __init early_init_fdt_scan_reserved_mem(void) of_scan_flat_dt(__fdt_scan_reserved_mem, NULL); fdt_init_reserved_mem(); + reserve_elfcorehdr(); } /** @@ -920,6 +946,32 @@ static inline void early_init_dt_check_for_initrd(unsigned long node) } #endif /* CONFIG_BLK_DEV_INITRD */ +/** + * early_init_dt_check_for_elfcorehdr - Decode elfcorehdr location from flat + * tree + * @node: reference to node containing elfcorehdr location ('chosen') + */ +static void __init early_init_dt_check_for_elfcorehdr(unsigned long node) +{ + const __be32 *prop; + int len; + + if (!IS_ENABLED(CONFIG_CRASH_DUMP)) + return; + + pr_debug("Looking for elfcorehdr property... "); + + prop = of_get_flat_dt_prop(node, "linux,elfcorehdr", &len); + if (!prop || (len < (dt_root_addr_cells + dt_root_size_cells))) + return; + + elfcorehdr_addr = dt_mem_next_cell(dt_root_addr_cells, &prop); + elfcorehdr_size = dt_mem_next_cell(dt_root_size_cells, &prop); + + pr_debug("elfcorehdr_start=0x%llx elfcorehdr_size=0x%llx\n", + elfcorehdr_addr, elfcorehdr_size); +} + #ifdef CONFIG_SERIAL_EARLYCON int __init early_init_dt_scan_chosen_stdout(void) @@ -1067,6 +1119,7 @@ int __init early_init_dt_scan_chosen(unsigned long node, const char *uname, return 0; early_init_dt_check_for_initrd(node); + early_init_dt_check_for_elfcorehdr(node); /* Retrieve command line */ p = of_get_flat_dt_prop(node, "bootargs", &l); @@ -1190,14 +1243,14 @@ void __init early_init_dt_scan_nodes(void) { int rc = 0; + /* Initialize {size,address}-cells info */ + of_scan_flat_dt(early_init_dt_scan_root, NULL); + /* Retrieve various information from the /chosen node */ rc = of_scan_flat_dt(early_init_dt_scan_chosen, boot_command_line); if (!rc) pr_warn("No chosen node found, continuing without\n"); - /* Initialize {size,address}-cells info */ - of_scan_flat_dt(early_init_dt_scan_root, NULL); - /* Setup memory, calling early_init_dt_add_memory_arch */ of_scan_flat_dt(early_init_dt_scan_memory, NULL); } -- cgit v1.2.3