Volume 2, Part 1: Addressing and Protection
2:57
Software can verify page level permissions by the
probe
(regular_form
probe
or
probe.fault
) instruction, which checks accessibility to a given virtual page by verifying
privilege levels, page level read and write permission, and protection key read and
write permission.
Execute-only pages (TLB.ar 7) can be used to promote the privilege level on entry into
the operating system. User level code would typically branch into a promotion page
(controlled by the operating system) and execute the Enter Privileged Code (
epc
)
instruction. When
epc
successfully promotes, the next instruction group is executed at
the target privilege level specified by the promotion page. A procedure return branch
type (
br.ret
) can demote the current privilege level.
4.1.1.7
Page Sizes
A range of page sizes are supported to assist software in mapping system resources
and improve TLB/VHPT utilization. Typically, operating systems will select a small range
of fixed page sizes to implement virtual memory algorithms. Larger pages may be
statically allocated. For example, large areas of the virtual address space may be
reserved for operating system kernels, frame buffers, or memory-mapped I/O regions.
Software may also elect to pin these translations, by placing them in the translation
registers.
lists insertable and purgeable page sizes that are supported by all processor
models. Insertable page sizes can be specified in the translation cache, the translation
registers, the region registers and the VHPT. Insertable page sizes can also be used as
parameters to TLB purge instructions (
ptc.l
,
ptc.g
,
ptc.ga
or
ptr
). Page sizes that
are purgeable only may only be used as parameters to TLB purge instructions.
Processors may also support additional insertable and purgeable page sizes. Please see
the processor-specific documentation for further information on the page sizes
supported by the Itanium processor.
6
3
RWX
RW
RW
RW
read, write, execute / read, write
2
–
RWX
RW
RW
1
–
–
RWX
RW
0
–
–
–
RW
7
3
X
X
X
RX
exec, promote
b
/ read, execute
2
XP2 X
X
RX
1
XP1
XP1
X
RX
0
XP0
XP0
XP0
RX
a. RSC.pl, for RSE fills and spills; PSR.cpl for all other accesses.
b. User execute only pages can be enforced by setting PL to 3.
Table 4-4.
Page Access Rights (Continued)
TLB.ar
TLB.pl
Privilege Level
a
Description
3
2
1
0
Содержание ITANIUM ARCHITECTURE - SOFTWARE DEVELOPERS VOLUME 3 REV 2.3
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Страница 11: ...x Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 12: ...1 1 Intel Itanium Architecture Software Developer s Manual Rev 2 3 Part I Application Architecture Guide ...
Страница 13: ...1 2 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 33: ...1 22 Volume 1 Part 1 Introduction to the Intel Itanium Architecture ...
Страница 57: ...1 46 Volume 1 Part 1 Execution Environment ...
Страница 147: ...1 136 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 149: ...1 138 Volume 1 Part 2 About the Optimization Guide ...
Страница 191: ...1 180 Volume 1 Part 2 Predication Control Flow and Instruction Stream ...
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Страница 248: ...236 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 249: ...2 1 Intel Itanium Architecture Software Developer s Manual Rev 2 3 Part I System Architecture Guide ...
Страница 250: ...2 2 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 264: ...2 16 Volume 2 Part 1 Intel Itanium System Environment ...
Страница 380: ...2 132 Volume 2 Part 1 Interruptions ...
Страница 398: ...2 150 Volume 2 Part 1 Register Stack Engine ...
Страница 486: ...2 238 Volume 2 Part 1 IA 32 Interruption Vector Descriptions ...
Страница 749: ...2 501 Intel Itanium Architecture Software Developer s Manual Rev 2 3 Part II System Programmer s Guide ...
Страница 750: ...2 502 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 754: ...2 506 Volume 2 Part 2 About the System Programmer s Guide ...
Страница 796: ...2 548 Volume 2 Part 2 Interruptions and Serialization ...
Страница 808: ...2 560 Volume 2 Part 2 Context Management ...
Страница 842: ...2 594 Volume 2 Part 2 Floating point System Software ...
Страница 850: ...2 602 Volume 2 Part 2 IA 32 Application Support ...
Страница 862: ...2 614 Volume 2 Part 2 External Interrupt Architecture ...
Страница 870: ...2 622 Volume 2 Part 2 Performance Monitoring Support ...
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Страница 941: ...3 42 Volume 3 Instruction Reference cmp illegal_operation_fault PR p1 0 PR p2 0 Interruptions Illegal Operation fault ...
Страница 1099: ...3 200 Volume 3 Instruction Reference padd Interruptions Illegal Operation fault ...
Страница 1191: ...3 292 Volume 3 Pseudo Code Functions Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 1295: ...3 396 Volume 3 Resource and Dependency Semantics ...
Страница 1296: ......
Страница 1302: ...402 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 1494: ...4 192 Volume 4 Base IA 32 Instruction Reference FWAIT Wait See entry for WAIT ...
Страница 1564: ...4 262 Volume 4 Base IA 32 Instruction Reference LES Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 1565: ...Volume 4 Base IA 32 Instruction Reference 4 263 LFS Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 1568: ...4 266 Volume 4 Base IA 32 Instruction Reference LGS Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 1583: ...Volume 4 Base IA 32 Instruction Reference 4 281 LSS Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 1647: ...Volume 4 Base IA 32 Instruction Reference 4 345 ROL ROR Rotate See entry for RCL RCR ROL ROR ...
Страница 1663: ...Volume 4 Base IA 32 Instruction Reference 4 361 SHL SHR Shift Instructions See entry for SAL SAR SHL SHR ...
Страница 1668: ...4 366 Volume 4 Base IA 32 Instruction Reference SIDT Store Interrupt Descriptor Table Register See entry for SGDT SIDT ...
Страница 1884: ...4 582 Volume 4 IA 32 SSE Instruction Reference ...
Страница 1885: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 Index ...
Страница 1886: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 1898: ...INDEX Index 12 Index for Volumes 1 2 3 and 4 ...