[PATCH] acpi: do not attempt to create EBDA on EFI (was: Loading DSDT table using 'acpi' or some memory write command?)

[Andrei Borzenkov <arvidjaar@gmail.com>]

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01.04.2017 12:09, Andrei Borzenkov пишет:
> 
> I also have rather weird issue that after "acpi dsdt.aml" I lose
> partitions (only hard disk itself is visible). This is on real hardware
> (Dell Latitude E5450).
> 
> 

Anyone knows why we attempt to write to some arbitrary memory location
on EFI in the first place?

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From: Andrei Borzenkov <arvidjaar@gmail.com>
Subject: [PATCH] acpi: do not attempt to create EBDA on EFI

There is no gurantee that BDA or EBDA on EFI exists; blindly writing
into memory will likely corrupt it. This fixed problem on Dell Latitude
E5450, where after loading ACPI table GRUB "lost" all disk partitions.

---
 grub-core/commands/acpi.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/grub-core/commands/acpi.c b/grub-core/commands/acpi.c
index 9f02f22..a395d74 100644
--- a/grub-core/commands/acpi.c
+++ b/grub-core/commands/acpi.c
@@ -119,7 +119,7 @@ grub_acpi_get_rsdpv1 (void)
   return grub_machine_acpi_get_rsdpv1 ();
 }
 
-#if defined (__i386__) || defined (__x86_64__)
+#if defined (__i386__) && !defined (GRUB_MACHINE_EFI)
 
 static inline int
 iszero (grub_uint8_t *reg, int size)
@@ -741,7 +741,7 @@ grub_cmd_acpi (struct grub_extcmd_context *ctxt, int argc, char **args)
     }
   acpi_tables = 0;
 
-#if defined (__i386__) || defined (__x86_64__)
+#if defined (__i386__) && !defined (GRUB_MACHINE_EFI)
   if (! state[9].set)
     {
       grub_err_t err;
-- 
tg: (007f0b4..) u/acpi-skip-ebda-on-efi (depends on: master)