[PATCH 43/50] x86/boot/e820: Simplify the e820__update_table() interface

From: Ingo Molnar
Date: Sat Jan 28 2017 - 17:48:10 EST


The e820__update_table() parameters are pretty complex:

arch/x86/include/asm/e820/api.h:extern int e820__update_table(struct e820_entry *biosmap, int max_nr_map, u32 *pnr_map);

But 90% of the usage is trivial:

arch/x86/kernel/e820.c: if (e820__update_table(e820_table->entries, ARRAY_SIZE(e820_table->entries), &e820_table->nr_entries))
arch/x86/kernel/e820.c: e820__update_table(e820_table->entries, ARRAY_SIZE(e820_table->entries), &e820_table->nr_entries);
arch/x86/kernel/e820.c: e820__update_table(e820_table->entries, ARRAY_SIZE(e820_table->entries), &e820_table->nr_entries);
arch/x86/kernel/e820.c: if (e820__update_table(e820_table->entries, ARRAY_SIZE(e820_table->entries), &e820_table->nr_entries) < 0)
arch/x86/kernel/e820.c: e820__update_table(boot_params.e820_table, ARRAY_SIZE(boot_params.e820_table), &new_nr);
arch/x86/kernel/early-quirks.c: e820__update_table(e820_table->entries, ARRAY_SIZE(e820_table->entries), &e820_table->nr_entries);
arch/x86/kernel/setup.c: e820__update_table(e820_table->entries, ARRAY_SIZE(e820_table->entries), &e820_table->nr_entries);
arch/x86/kernel/setup.c: e820__update_table(e820_table->entries, ARRAY_SIZE(e820_table->entries), &e820_table->nr_entries);
arch/x86/platform/efi/efi.c: e820__update_table(e820_table->entries, ARRAY_SIZE(e820_table->entries), &e820_table->nr_entries);
arch/x86/xen/setup.c: e820__update_table(xen_e820_table.entries, ARRAY_SIZE(xen_e820_table.entries),
arch/x86/xen/setup.c: e820__update_table(e820_table->entries, ARRAY_SIZE(e820_table->entries), &e820_table->nr_entries);
arch/x86/xen/setup.c: e820__update_table(xen_e820_table.entries, ARRAY_SIZE(xen_e820_table.entries),

as it only uses an exiting struct e820_table's entries array, its size and
its current number of entries as input and output arguments.

Only one use is non-trivial:

arch/x86/kernel/e820.c: e820__update_table(boot_params.e820_table, ARRAY_SIZE(boot_params.e820_table), &new_nr);

... which call updates the E820 table in the zeropage in-situ, and the layout there does not
match that of 'struct e820_table' (in particular nr_entries is at a different offset,
hardcoded by the boot protocol).

Simplify all this by introducing a low level __e820__update_table() API that
the zeropage update call can use, and simplifying the main e820__update_table()
call signature down to:

int e820__update_table(struct e820_table *table);

This visibly simplifies all the call sites:

arch/x86/include/asm/e820/api.h:extern int e820__update_table(struct e820_table *table);
arch/x86/include/asm/e820/types.h: * call to e820__update_table() to remove duplicates. The allowance
arch/x86/kernel/e820.c: * The return value from e820__update_table() is zero if it
arch/x86/kernel/e820.c:int __init e820__update_table(struct e820_table *table)
arch/x86/kernel/e820.c: if (e820__update_table(e820_table))
arch/x86/kernel/e820.c: e820__update_table(e820_table_firmware);
arch/x86/kernel/e820.c: e820__update_table(e820_table);
arch/x86/kernel/e820.c: e820__update_table(e820_table);
arch/x86/kernel/e820.c: if (e820__update_table(e820_table) < 0)
arch/x86/kernel/early-quirks.c: e820__update_table(e820_table);
arch/x86/kernel/setup.c: e820__update_table(e820_table);
arch/x86/kernel/setup.c: e820__update_table(e820_table);
arch/x86/platform/efi/efi.c: e820__update_table(e820_table);
arch/x86/xen/setup.c: e820__update_table(&xen_e820_table);
arch/x86/xen/setup.c: e820__update_table(e820_table);
arch/x86/xen/setup.c: e820__update_table(&xen_e820_table);

No change in functionality.

Cc: Alex Thorlton <athorlton@xxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Huang, Ying <ying.huang@xxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Juergen Gross <jgross@xxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Paul Jackson <pj@xxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Rafael J. Wysocki <rjw@xxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Wei Yang <richard.weiyang@xxxxxxxxx>
Cc: Yinghai Lu <yinghai@xxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/include/asm/e820/api.h | 2 +-
arch/x86/kernel/e820.c | 19 ++++++++++++-------
arch/x86/kernel/early-quirks.c | 2 +-
arch/x86/kernel/setup.c | 4 ++--
arch/x86/platform/efi/efi.c | 2 +-
arch/x86/xen/setup.c | 9 ++++-----
6 files changed, 21 insertions(+), 17 deletions(-)

diff --git a/arch/x86/include/asm/e820/api.h b/arch/x86/include/asm/e820/api.h
index 4c35c36c62d5..7d5dfc2f9e91 100644
--- a/arch/x86/include/asm/e820/api.h
+++ b/arch/x86/include/asm/e820/api.h
@@ -16,7 +16,7 @@ extern u64 e820__range_update(u64 start, u64 size, enum e820_type old_type, enu
extern u64 e820__range_remove(u64 start, u64 size, enum e820_type old_type, int checktype);

extern void e820__print_table(char *who);
-extern int e820__update_table(struct e820_entry *biosmap, int max_nr_map, u32 *pnr_map);
+extern int e820__update_table(struct e820_table *table);
extern void e820__update_table_print(void);

extern unsigned long e820_end_of_ram_pfn(void);
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index da69addf6c34..49823e0a7aea 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -259,7 +259,7 @@ static int __init cpcompare(const void *a, const void *b)
return (ap->addr != ap->pbios->addr) - (bp->addr != bp->pbios->addr);
}

-int __init e820__update_table(struct e820_entry *biosmap, int max_nr_map, u32 *pnr_map)
+static int __init __e820__update_table(struct e820_entry *biosmap, int max_nr_map, u32 *pnr_map)
{
static struct change_member change_point_list[2*E820_MAX_ENTRIES] __initdata;
static struct change_member *change_point[2*E820_MAX_ENTRIES] __initdata;
@@ -368,6 +368,11 @@ int __init e820__update_table(struct e820_entry *biosmap, int max_nr_map, u32 *p
return 0;
}

+int __init e820__update_table(struct e820_table *table)
+{
+ return __e820__update_table(table->entries, ARRAY_SIZE(table->entries), &table->nr_entries);
+}
+
static int __init __append_e820_table(struct e820_entry *biosmap, int nr_map)
{
while (nr_map) {
@@ -548,7 +553,7 @@ u64 __init e820__range_remove(u64 start, u64 size, enum e820_type old_type, int

void __init e820__update_table_print(void)
{
- if (e820__update_table(e820_table->entries, ARRAY_SIZE(e820_table->entries), &e820_table->nr_entries))
+ if (e820__update_table(e820_table))
return;

pr_info("e820: modified physical RAM map:\n");
@@ -557,7 +562,7 @@ void __init e820__update_table_print(void)

static void __init e820__update_table_firmware(void)
{
- e820__update_table(e820_table_firmware->entries, ARRAY_SIZE(e820_table_firmware->entries), &e820_table_firmware->nr_entries);
+ e820__update_table(e820_table_firmware);
}

#define MAX_GAP_END 0x100000000ull
@@ -676,7 +681,7 @@ void __init e820__memory_setup_extended(u64 phys_addr, u32 data_len)
extmap = (struct e820_entry *)(sdata->data);

__append_e820_table(extmap, entries);
- e820__update_table(e820_table->entries, ARRAY_SIZE(e820_table->entries), &e820_table->nr_entries);
+ e820__update_table(e820_table);

early_memunmap(sdata, data_len);
pr_info("e820: extended physical RAM map:\n");
@@ -931,7 +936,7 @@ void __init e820_reserve_setup_data(void)
early_memunmap(data, sizeof(*data));
}

- e820__update_table(e820_table->entries, ARRAY_SIZE(e820_table->entries), &e820_table->nr_entries);
+ e820__update_table(e820_table);
memcpy(e820_table_firmware, e820_table, sizeof(*e820_table_firmware));
printk(KERN_INFO "extended physical RAM map:\n");
e820__print_table("reserve setup_data");
@@ -945,7 +950,7 @@ void __init e820_reserve_setup_data(void)
void __init e820__finish_early_params(void)
{
if (userdef) {
- if (e820__update_table(e820_table->entries, ARRAY_SIZE(e820_table->entries), &e820_table->nr_entries) < 0)
+ if (e820__update_table(e820_table) < 0)
early_panic("Invalid user supplied memory map");

pr_info("e820: user-defined physical RAM map:\n");
@@ -1132,7 +1137,7 @@ char *__init e820__memory_setup_default(void)
* the next section from 1mb->appropriate_mem_k
*/
new_nr = boot_params.e820_entries;
- e820__update_table(boot_params.e820_table, ARRAY_SIZE(boot_params.e820_table), &new_nr);
+ __e820__update_table(boot_params.e820_table, ARRAY_SIZE(boot_params.e820_table), &new_nr);
boot_params.e820_entries = new_nr;

if (append_e820_table(boot_params.e820_table, boot_params.e820_entries) < 0) {
diff --git a/arch/x86/kernel/early-quirks.c b/arch/x86/kernel/early-quirks.c
index 2220a4c03adf..ff7e4b3988ed 100644
--- a/arch/x86/kernel/early-quirks.c
+++ b/arch/x86/kernel/early-quirks.c
@@ -547,7 +547,7 @@ intel_graphics_stolen(int num, int slot, int func,

/* Mark this space as reserved */
e820__range_add(base, size, E820_TYPE_RESERVED);
- e820__update_table(e820_table->entries, ARRAY_SIZE(e820_table->entries), &e820_table->nr_entries);
+ e820__update_table(e820_table);
}

static void __init intel_graphics_quirks(int num, int slot, int func)
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 074c86a0ee86..acb2db02ec81 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -740,7 +740,7 @@ static void __init trim_bios_range(void)
*/
e820__range_remove(BIOS_BEGIN, BIOS_END - BIOS_BEGIN, E820_TYPE_RAM, 1);

- e820__update_table(e820_table->entries, ARRAY_SIZE(e820_table->entries), &e820_table->nr_entries);
+ e820__update_table(e820_table);
}

/* called before trim_bios_range() to spare extra sanitize */
@@ -1033,7 +1033,7 @@ void __init setup_arch(char **cmdline_p)
if (ppro_with_ram_bug()) {
e820__range_update(0x70000000ULL, 0x40000ULL, E820_TYPE_RAM,
E820_TYPE_RESERVED);
- e820__update_table(e820_table->entries, ARRAY_SIZE(e820_table->entries), &e820_table->nr_entries);
+ e820__update_table(e820_table);
printk(KERN_INFO "fixed physical RAM map:\n");
e820__print_table("bad_ppro");
}
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 14d0a6b1eee1..2f7f7605fee0 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -167,7 +167,7 @@ static void __init do_add_efi_memmap(void)
}
e820__range_add(start, size, e820_type);
}
- e820__update_table(e820_table->entries, ARRAY_SIZE(e820_table->entries), &e820_table->nr_entries);
+ e820__update_table(e820_table);
}

int __init efi_memblock_x86_reserve_range(void)
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index cf29abfc392c..a5bf7c451435 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -782,7 +782,7 @@ char * __init xen_memory_setup(void)
xen_ignore_unusable();

/* Make sure the Xen-supplied memory map is well-ordered. */
- e820__update_table(xen_e820_table.entries, ARRAY_SIZE(xen_e820_table.entries), &xen_e820_table.nr_entries);
+ e820__update_table(&xen_e820_table);

max_pages = xen_get_max_pages();

@@ -856,10 +856,9 @@ char * __init xen_memory_setup(void)
* reserve ISA memory anyway because too many things poke
* about in there.
*/
- e820__range_add(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS,
- E820_TYPE_RESERVED);
+ e820__range_add(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS, E820_TYPE_RESERVED);

- e820__update_table(e820_table->entries, ARRAY_SIZE(e820_table->entries), &e820_table->nr_entries);
+ e820__update_table(e820_table);

/*
* Check whether the kernel itself conflicts with the target E820 map.
@@ -930,7 +929,7 @@ char * __init xen_auto_xlated_memory_setup(void)

xen_e820_table.nr_entries = memmap.nr_entries;

- e820__update_table(xen_e820_table.entries, ARRAY_SIZE(xen_e820_table.entries), &xen_e820_table.nr_entries);
+ e820__update_table(&xen_e820_table);

for (i = 0; i < xen_e820_table.nr_entries; i++)
e820__range_add(xen_e820_table.entries[i].addr, xen_e820_table.entries[i].size, xen_e820_table.entries[i].type);
--
2.7.4