tree 987dfc6323ad0b1bdc27121b5dc73e3513054157
parent 3f36a8c7e15233a1b516f06bfa1b068f7bb34147
author Michael Niewöhner <foss@mniewoehner.de> 1618937502 +0200
committer Patrick Georgi <pgeorgi@google.com> 1619764868 +0000

cpu/x86/msr: introduce helpers msr_read, msr_write

The existing helpers for reading/writing MSRs (rdmsr, wrmsr) require use
of the struct `msr_t`, which splits the MSR value into two 32 bit parts.
In many cases, where simple 32 bit or 64 bit values are written, this
bloats the code by unnecessarly having to use that struct.

Thus, introduce the helpers `msr_read` and `msr_write`, which take or
return `uint64_t` values, so the code condenses to a single line or two,
without having to deal with `msr_t`.

Example 1:

~~~
msr_t msr = {
  .lo = read32((void *)(uintptr_t)0xfed30880),
  .hi = 0,
};

msr.lo |= 1;
wrmsr(0x123, msr);
~~~

becomes

~~~
uint32_t foo = read32((void *)(uintptr_t)0xfed30880);
msr_write(0x123, foo | 1)
~~~

Example 2:

~~~
msr_t msr = rdmsr(0xff);
uint64_t msr_val = (msr.hi << 32) | msr.lo;
~~~

becomes

~~~
uint64_t msr_val = msr_read(0xff);
~~~

Change-Id: I27333a4bdfe3c8cebfe49a16a4f1a066f558c4ce
Signed-off-by: Michael Niewöhner <foss@mniewoehner.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/52548
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>