Le 17/07/2019 à 10:06, Jason Yan a écrit :
One may want to disable kaslr when boot, so provide a cmdline parameter
'nokaslr' to support this.

Signed-off-by: Jason Yan <yanai...@huawei.com>
Cc: Diana Craciun <diana.crac...@nxp.com>
Cc: Michael Ellerman <m...@ellerman.id.au>
Cc: Christophe Leroy <christophe.le...@c-s.fr>
Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
Cc: Paul Mackerras <pau...@samba.org>
Cc: Nicholas Piggin <npig...@gmail.com>
Cc: Kees Cook <keesc...@chromium.org>
---
  arch/powerpc/kernel/kaslr_booke.c | 14 ++++++++++++++
  1 file changed, 14 insertions(+)

diff --git a/arch/powerpc/kernel/kaslr_booke.c 
b/arch/powerpc/kernel/kaslr_booke.c
index 00339c05879f..e65a5d9d2ff1 100644
--- a/arch/powerpc/kernel/kaslr_booke.c
+++ b/arch/powerpc/kernel/kaslr_booke.c
@@ -373,6 +373,18 @@ static unsigned long __init kaslr_choose_location(void 
*dt_ptr, phys_addr_t size
        return kaslr_offset;
  }
+static inline __init bool kaslr_disabled(void)
+{
+       char *str;
+
+       str = strstr(early_command_line, "nokaslr");

Why using early_command_line instead of boot_command_line ?


+       if ((str == early_command_line) ||
+           (str > early_command_line && *(str - 1) == ' '))

Is that stuff really needed ?

Why not just:

return strstr(early_command_line, "nokaslr") != NULL;

+               return true;
+
+       return false;
+}


+
  /*
   * To see if we need to relocate the kernel to a random offset
   * void *dt_ptr - address of the device tree
@@ -388,6 +400,8 @@ notrace void __init kaslr_early_init(void *dt_ptr, 
phys_addr_t size)
        kernel_sz = (unsigned long)_end - KERNELBASE;
kaslr_get_cmdline(dt_ptr);
+       if (kaslr_disabled())
+               return;
offset = kaslr_choose_location(dt_ptr, size, kernel_sz);

Christophe

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