Messages in this thread | | | Subject | Re: [PATCH v4 3/4] x86/boot/KASLR: Walk srat tables to filter immovable memory | From | Dou Liyang <> | Date | Thu, 2 Aug 2018 11:47:13 +0800 |
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Hi Fan,
At 07/23/2018 05:29 PM, Chao Fan wrote: > If 'CONFIG_MEMORY_HOTREMOVE' specified, walk the acpi srat memory > tables, store the immovable memory regions, so that kaslr can get > the information abouth where can be selected or not. > If 'CONFIG_MEMORY_HOTREMOVE' not specified, go on the old code. > > Signed-off-by: Chao Fan <fanc.fnst@cn.fujitsu.com> > --- > arch/x86/boot/compressed/kaslr.c | 55 ++++++++++++++++++++++++++++++++ > 1 file changed, 55 insertions(+) > > diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c > index 531c9876f573..4705682caf1f 100644 > --- a/arch/x86/boot/compressed/kaslr.c > +++ b/arch/x86/boot/compressed/kaslr.c > @@ -31,6 +31,7 @@ > > #include "misc.h" > #include "error.h" > +#include "acpitb.h" > #include "../string.h" > > #include <generated/compile.h> > @@ -104,6 +105,14 @@ static bool memmap_too_large; > /* Store memory limit specified by "mem=nn[KMG]" or "memmap=nn[KMG]" */ > unsigned long long mem_limit = ULLONG_MAX; > > +#ifdef CONFIG_MEMORY_HOTREMOVE > +/* Store the immovable memory regions */ > +struct mem_vector immovable_mem[]; > + > +/* Store the amount of immovable memory regions */ > +static int num_immovable_mem; > +#endif > + > > enum mem_avoid_index { > MEM_AVOID_ZO_RANGE = 0, > @@ -298,6 +307,47 @@ static int handle_mem_options(void) > return 0; > } > > +#ifdef CONFIG_MEMORY_HOTREMOVE > +/* > + * According to ACPI table, filter the immvoable memory regions > + * and store them in immovable_mem[]. > + */ > +static void handle_immovable_mem(void) > +{ > + struct acpi_table_header *table_header; > + struct acpi_subtable_header *table; > + struct acpi_srat_mem_affinity *ma; > + unsigned long table_size; > + unsigned long table_end; > + int i = 0; > + > + table_header = get_acpi_srat_table(); > + > + if (!table_header) > + return; > + > + table_end = (unsigned long)table_header + table_header->length; > + > + table = (struct acpi_subtable_header *) > + ((unsigned long)table_header + sizeof(struct acpi_table_srat)); > + > + table_size = sizeof(struct acpi_subtable_header);
table_size isn't used, can be remove.
> + while (((unsigned long)table) + table->length < table_end) { > + if (table->type == 1) { > + ma = (struct acpi_srat_mem_affinity *)table; > + if (!(ma->flags & ACPI_SRAT_MEM_HOT_PLUGGABLE)) { > + immovable_mem[i].start = ma->base_address; > + immovable_mem[i].size = ma->length; > + i++;
need a check(i < MAX_NUMNODES*2) before doing that in case of __IndexOutOfBoundsException__ even if it may be impossible in ACPI.
Thanks, dou > + } > + } > + table = (struct acpi_subtable_header *) > + ((unsigned long)table + table->length); > + } > + num_immovable_mem = i; > +} > +#endif > + > /* > * In theory, KASLR can put the kernel anywhere in the range of [16M, 64T). > * The mem_avoid array is used to store the ranges that need to be avoided > @@ -421,6 +471,11 @@ static void mem_avoid_init(unsigned long input, unsigned long input_size, > /* Mark the memmap regions we need to avoid */ > handle_mem_options(); > > +#ifdef CONFIG_MEMORY_HOTREMOVE > + /* Mark the immovable regions we need to choose */ > + handle_immovable_mem(); > +#endif > + > #ifdef CONFIG_X86_VERBOSE_BOOTUP > /* Make sure video RAM can be used. */ > add_identity_map(0, PMD_SIZE); >
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