Commit Graph

2 Commits

Author SHA1 Message Date
Daniel Kiper
acc726f812 x86/msr: Fix build with older GCC versions
Some older GCC versions produce following error when x86 MSR modules are build:

  In file included from commands/i386/rdmsr.c:29:0:
  ../include/grub/i386/rdmsr.h:27:29: error: no previous prototype for ‘grub_msr_read’ [-Werror=missing-prototypes]
   extern inline grub_uint64_t grub_msr_read (grub_uint32_t msr_id)
                               ^
  cc1: all warnings being treated as errors

This happens due to lack of support for a such usage of extern keyword
in older GCCs. Additionally, this usage is not consistent with the rest
of codebase. So, replace it with static keyword.

Additionally, fix incorrect coding style.

Reported-by: Eric Snowberg <eric.snowberg@oracle.com>
Reported-by: adrian15 <adrian15sgd@gmail.com>
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Vladimir 'phcoder' Serbinenko <phcoder@gmail.com>
Reviewed-by: Eric Snowberg <eric.snowberg@oracle.com>
Tested-by: adrian15 <adrian15sgd@gmail.com>
2019-04-23 11:04:07 +02:00
Jesús Diéguez Fernández
46f5d51343 msr: Add new MSR modules (rdmsr/wrmsr)
In order to be able to read from and write to model-specific registers,
two new modules are added. They are i386 specific, as the cpuid module.

rdmsr module registers the command rdmsr that allows reading from a MSR.
wrmsr module registers the command wrmsr that allows writing to a MSR.

wrmsr module is disabled if UEFI secure boot is enabled.

Please note that on SMP systems, interacting with a MSR that has a scope
per hardware thread, implies that the value only applies to the
particular cpu/core/thread that ran the command.

Also, if you specify a reserved or unimplemented MSR address, it will
cause a general protection exception (which is not currently being
handled) and the system will reboot.

Signed-off-by: Jesús Diéguez Fernández <jesusdf@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2019-03-12 20:04:07 +01:00