[PATCH v2 11/13] x86: use io_remap to access real_mode_data

From: Yinghai Lu
Date: Sun Nov 18 2012 - 02:11:05 EST


When 64bit bootloader put real mode data above 4g, We can not
access real mode data directly.

because in arch/x86/kernel/head_64.S, only set ident mapping
for 0-1g, and kernel code/data/bss.

So need to move early_ioremap_init() calling from setup_arch
to x86_64_start_kernel.

Also use rsi/rdi instead of esi/edi.

Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
---
arch/x86/kernel/head64.c | 17 ++++++++++++++---
arch/x86/kernel/head_64.S | 4 ++--
arch/x86/kernel/setup.c | 2 ++
3 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 3ac6cad..ca00d73 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -52,12 +52,21 @@ static void __init copy_bootdata(char *real_mode_data)
{
char * command_line;
unsigned long cmd_line_ptr;
+ char *p;

- memcpy(&boot_params, real_mode_data, sizeof boot_params);
+ /*
+ * for 64bit bootload path, those data could be above 4G,
+ * and we do set ident mapping for them in head_64.S.
+ * So need to ioremap to access them.
+ */
+ p = early_memremap((unsigned long)real_mode_data, sizeof boot_params);
+ memcpy(&boot_params, p, sizeof boot_params);
+ early_iounmap(p, sizeof boot_params);
cmd_line_ptr = get_cmd_line_ptr();
if (cmd_line_ptr) {
- command_line = __va(cmd_line_ptr);
+ command_line = early_memremap(cmd_line_ptr, COMMAND_LINE_SIZE);
memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
+ early_iounmap(command_line, COMMAND_LINE_SIZE);
}
}

@@ -104,7 +113,9 @@ void __init x86_64_start_kernel(char * real_mode_data)

void __init x86_64_start_reservations(char *real_mode_data)
{
- copy_bootdata(__va(real_mode_data));
+ early_ioremap_init();
+
+ copy_bootdata(real_mode_data);

memblock_reserve(__pa_symbol(&_text),
__pa_symbol(&__bss_stop) - __pa_symbol(&_text));
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 32fa9d0..14c5de2 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -262,9 +262,9 @@ ENTRY(secondary_startup_64)
movl initial_gs+4(%rip),%edx
wrmsr

- /* esi is pointer to real mode structure with interesting info.
+ /* rsi is pointer to real mode structure with interesting info.
pass it to C */
- movl %esi, %edi
+ movq %rsi, %rdi

/* Finally jump to run C code and to be on real kernel address
* Since we are running on identity-mapped space we have to jump
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 194e151..573fa7d7 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -718,7 +718,9 @@ void __init setup_arch(char **cmdline_p)

early_trap_init();
early_cpu_init();
+#ifdef CONFIG_X86_32
early_ioremap_init();
+#endif

setup_olpc_ofw_pgd();

--
1.7.7

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