From 5da217ca967b9d7a0bbbd8edd06749c99a4fe501 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Sat, 28 Jan 2017 13:46:28 +0100 Subject: [PATCH] x86/boot/e820: Rename early_reserve_e820() to e820__memblock_alloc() and document it early_reserve_e820() is an early hack for kexec that does a limited fixup of the mptable and passes it to the kexec kernel as if it was the real thing. For this it needs to allocate memory - but no memory allocator is available yet beyond the memblock allocator, so early_reserve_e820() is really a wrapper around memblock_alloc() plus a hack to update the e820_table_firmware entries. The name 'reserve' is really a bit of a misnomer, as 'reserved' memory typically means memory completely inaccessible to the kernel - while here what we want to do is a special RAM allocation for our own purposes and insert that as RAM_RESERVED. Rename the function to e820__memblock_alloc_reserved() to better signal this dual purpose, plus document it better, which was omitted when it was merged. The barely comprehensible and cryptic comment: /* * pre allocated 4k and reserved it in memblock and e820_table_firmware */ u64 __init e820__memblock_alloc_reserved(u64 size, u64 align) ... does not count as documentation, replace it with: /* * Allocate the requested number of bytes with the requsted alignment * and return (the physical address) to the caller. Also register this * range in the 'firmware' E820 table. * * This allows kexec to fake a new mptable, as if it came from the real * system. */ u64 __init e820__memblock_alloc_reserved(u64 size, u64 align) No change in functionality. Cc: Alex Thorlton Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Dan Williams Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Huang, Ying Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Linus Torvalds Cc: Paul Jackson Cc: Peter Zijlstra Cc: Rafael J. Wysocki Cc: Tejun Heo Cc: Thomas Gleixner Cc: Wei Yang Cc: Yinghai Lu Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar --- arch/x86/include/asm/e820/api.h | 2 +- arch/x86/include/asm/mpspec.h | 4 ++-- arch/x86/kernel/e820.c | 11 ++++++++--- arch/x86/kernel/mpparse.c | 4 ++-- arch/x86/kernel/setup.c | 2 +- 5 files changed, 14 insertions(+), 9 deletions(-) diff --git a/arch/x86/include/asm/e820/api.h b/arch/x86/include/asm/e820/api.h index 0162581b0cae..3fdc0612d762 100644 --- a/arch/x86/include/asm/e820/api.h +++ b/arch/x86/include/asm/e820/api.h @@ -20,7 +20,7 @@ extern void e820_setup_gap(void); extern void e820__memory_setup_extended(u64 phys_addr, u32 data_len); extern unsigned long e820_end_of_ram_pfn(void); extern unsigned long e820_end_of_low_ram_pfn(void); -extern u64 early_reserve_e820(u64 sizet, u64 align); +extern u64 e820__memblock_alloc_reserved(u64 sizet, u64 align); extern void e820__memblock_setup(void); extern void e820_reserve_setup_data(void); extern void e820__finish_early_params(void); diff --git a/arch/x86/include/asm/mpspec.h b/arch/x86/include/asm/mpspec.h index 32007041ef8c..831eb7895535 100644 --- a/arch/x86/include/asm/mpspec.h +++ b/arch/x86/include/asm/mpspec.h @@ -64,7 +64,7 @@ static inline void find_smp_config(void) } #ifdef CONFIG_X86_MPPARSE -extern void early_reserve_e820_mpc_new(void); +extern void e820__memblock_alloc_reserved_mpc_new(void); extern int enable_update_mptable; extern int default_mpc_apic_id(struct mpc_cpu *m); extern void default_smp_read_mpc_oem(struct mpc_table *mpc); @@ -76,7 +76,7 @@ extern void default_mpc_oem_bus_info(struct mpc_bus *m, char *str); extern void default_find_smp_config(void); extern void default_get_smp_config(unsigned int early); #else -static inline void early_reserve_e820_mpc_new(void) { } +static inline void e820__memblock_alloc_reserved_mpc_new(void) { } #define enable_update_mptable 0 #define default_mpc_apic_id NULL #define default_smp_read_mpc_oem NULL diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c index 904ddb1343f2..93b5e3e5a3f0 100644 --- a/arch/x86/kernel/e820.c +++ b/arch/x86/kernel/e820.c @@ -734,16 +734,21 @@ core_initcall(e820_mark_nvs_memory); #endif /* - * pre allocated 4k and reserved it in memblock and e820_table_firmware + * Allocate the requested number of bytes with the requsted alignment + * and return (the physical address) to the caller. Also register this + * range in the 'firmware' E820 table as a reserved range. + * + * This allows kexec to fake a new mptable, as if it came from the real + * system. */ -u64 __init early_reserve_e820(u64 size, u64 align) +u64 __init e820__memblock_alloc_reserved(u64 size, u64 align) { u64 addr; addr = __memblock_alloc_base(size, align, MEMBLOCK_ALLOC_ACCESSIBLE); if (addr) { e820_update_range_firmware(addr, size, E820_RAM, E820_RESERVED); - pr_info("e820: update e820_table_firmware for early_reserve_e820\n"); + pr_info("e820: update e820_table_firmware for e820__memblock_alloc_reserved()\n"); update_e820_table_firmware(); } diff --git a/arch/x86/kernel/mpparse.c b/arch/x86/kernel/mpparse.c index 1e3320788510..0d904d759ff1 100644 --- a/arch/x86/kernel/mpparse.c +++ b/arch/x86/kernel/mpparse.c @@ -826,10 +826,10 @@ static int __init parse_alloc_mptable_opt(char *p) } early_param("alloc_mptable", parse_alloc_mptable_opt); -void __init early_reserve_e820_mpc_new(void) +void __init e820__memblock_alloc_reserved_mpc_new(void) { if (enable_update_mptable && alloc_mptable) - mpc_new_phys = early_reserve_e820(mpc_new_length, 4); + mpc_new_phys = e820__memblock_alloc_reserved(mpc_new_length, 4); } static int __init update_mp_table(void) diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index a121e01d8a4d..a31c5bc99635 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -1112,7 +1112,7 @@ void __init setup_arch(char **cmdline_p) } /* preallocate 4k for mptable mpc */ - early_reserve_e820_mpc_new(); + e820__memblock_alloc_reserved_mpc_new(); #ifdef CONFIG_X86_CHECK_BIOS_CORRUPTION setup_bios_corruption_check(); -- 2.39.5