[PATCH v4 09/11] x86: use io_remap to access real_mode_data

[Yinghai Lu]

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

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 early from setup_arch()
to x86_64_start_kernel().

Also use rsi/rdi instead of esi/edi for real_data pointer passing
between asm code and c code.

Signed-off-by: Yinghai Lu <ying...@kernel.org>
---
 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..735cd47 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 036dd0e..4e90af7 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -358,9 +358,9 @@ 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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