Intel ITANIUM ARCHITECTURE - SOFTWARE DEVELOPERS VOLUME 3 REV 2.3, Manual

Page: 686 / 1898

2:438 Volume 2, Part 1: Processor Abstraction Layer
PAL_MEMORY_BUFFER
PAL_MEMORY_BUFFER – Allocate a cacheable memory buffer for
exclusive PAL usage (277)
Purpose:
Provides cacheable memory to PAL for exclusive use during runtime.
Calling Conv:
Stacked
Mode:
Physical
Buffer:
Not dependent
Arguments:
Returns:
Status:
Description:
This procedure is used to provide PAL firmware a cacheable memory buffer for its
exclusive use as well as the ability to relocate this buffer at a later point in time if
necessary. PAL provides information at reset hand-off about the minimum buffer size
required by this procedure, and also indicates if this procedure is required to be called
for correct functionality of the processor. See
Section 11.2.2, “PALE_RESET Exit State”
on page 2:289 for additional information on the reset hand-off state.
The
base_address
input argument specifies the beginning address for the memory
buffer. The
alloc_size
input argument specifies the size of the memory buffer allocated
for PAL use. The minimum alignment requirement for this buffer is 4K. If the
base_address
is not at least 4K aligned, the procedure will return an invalid argument. If
the
alloc_size
input argument is smaller than the minimum size passed at PAL reset
handoff state, the procedure will return an invalid argument and provide the minimum
size required in the
min_size
return argument.
The
control_word
input argument specifies if this procedure is being used to register the
memory buffer or if it is being used to relocate the memory buffer. The format of the
control_word
is shown in Table 11-109 .
Argument Description
index Index of PAL_MEMORY_BUFFER within the list of PAL procedures.
base_address Physical address of the memory buffer allocated for PAL use.
alloc_size Unsigned integer denoting the size of the memory buffer.
control_word Formatted bit vector that provides control options for this procedure. See Table 11-109 .
Return Value Description
status Return status of the PAL_MEMORY_BUFFER procedure.
min_size Returns the minimum size of the memory buffer required if the alloc_size input argument was
not large enough.
Reserved 0
Reserved 0
Status Value Description
1 Call has not completed a buffer relocation due to a pending interrupt
0 Call completed without error
-1 Unimplemented procedure
-2 Invalid argument
-3 Call completed with error
Table 11-109. control_word Layout
Field Bits Description
reg 0 Value of 0 indicates registration for the first time of the buffer. A value of 1
indicates a relocation of the buffer.
int 1 Value of 1 indicates that the procedure should periodically poll for pending
external interrupts. If this value is 0, interrupts will be masked during the
execution of the entire procedure.
Reserved 63:2 Reserved