[PATCH 1/2] x86: early_memremap exact size of struct setup_data

From: WANG Chao
Date: Wed Jan 07 2015 - 05:56:33 EST


When early remapping setup_data, we can remap the structure alone, use
sizeof(struct setup_data). No need to remap a larger area, we never
access setup_data->data at that point.

Signed-off-by: WANG Chao <chaowang@xxxxxxxxxx>
---
arch/x86/kernel/setup.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index ab4734e..c4648ada 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -431,15 +431,13 @@ static void __init parse_setup_data(void)

pa_data = boot_params.hdr.setup_data;
while (pa_data) {
- u32 data_len, map_len, data_type;
+ u32 data_len, data_type;

- map_len = max(PAGE_SIZE - (pa_data & ~PAGE_MASK),
- (u64)sizeof(struct setup_data));
- data = early_memremap(pa_data, map_len);
+ data = early_memremap(pa_data, sizeof(*data));
data_len = data->len + sizeof(struct setup_data);
data_type = data->type;
pa_next = data->next;
- early_iounmap(data, map_len);
+ early_iounmap(data, sizeof(*data));

switch (data_type) {
case SETUP_E820_EXT:
--
2.1.0

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