Intel ITANIUM ARCHITECTURE - SOFTWARE DEVELOPERS MANUAL VOLUME 1 REV 2.3 Manual page 551

area is architectural state needed by the PAL code to resume during MCA and INIT
events (architected min-state save area + reserved). The remaining space in the buffer
is a scratch space reserved exclusively for PAL use, therefore SAL and OS must not use
this area. The layout of the processor min-state save area is shown in
The processor min-state save area is 4KB in size and must be in an uncacheable region.
The first 1KB of this area is architectural state needed by the PAL code to resume
during MCA and INIT events (architected min-state save area + reserved). The
remaining 3KB is a scratch buffer reserved exclusively for PAL use, therefore SAL and
OS must not use this area. The layout of the processor min-state save area is shown in
Figure 11-1.
Figure 11-1.
Min-state save ptr + 1KB
Min-state save ptr
The layout for the processors portion of the architectural 1KB processor min-state save
area is shown in
pointer to offset zero of the area. When PALE_CHECK is entered as a result of a
machine check, it fills in processor state, processes the machine check, and branches to
SALE_ENTRY with a pointer to the first available memory location that SAL can use in
GR16. SAL may allocate a variable sized area above the address passed in GR16 up to
the 1KB architectural limit, but this is internal to SAL and not known to PAL.
The base address of the min-state save area must minimally be aligned to a 512-byte
boundary, but larger alignments are allowed. All saves and restores to and from the
min-state save area are made using 8-byte wide load and store instructions. If the
processor min-state save area is not registered via the PAL_MC_REGISTER_MEM
procedure prior to the machine check, software recovery is not possible.
Volume 2, Part 1: Processor Abstraction Layer
Processor Min-state Save Area Layout
Min-state save ptr +
MIN_STATE_REQ
Figure 11-2. When SAL registers the area with PAL, it passes in a
PAL Reserved Memory
Architectural
Figure 11-1.
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