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Function memcpy_real() is an univeral data mover that does not require DAT mode to be able reading from a physical address. Its advantage is an ability to read from any address, even those for which no kernel virtual mapping exists. Although memcpy_real() is interrupt-safe, there are no handlers that make use of this function. The compiler instrumentation have to be disabled and separate no-DAT stack used to allow execution of the function once DAT mode is disabled. Rework memcpy_real() to overcome these shortcomings. As result, data copying (which is primarily reading out a crashed system memory by a user process) is executed on a regular stack with enabled interrupts. Also, use of memcpy_real_buf swap buffer becomes unnecessary and the swapping is eliminated. The above is achieved by using a fixed virtual address range that spans a single page and remaps that page repeatedly when memcpy_real() is called for a particular physical address. Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> |
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| .gitignore | ||
| als.c | ||
| boot.h | ||
| clz_ctz.c | ||
| cmdline.c | ||
| ctype.c | ||
| decompressor.c | ||
| decompressor.h | ||
| ebcdic.c | ||
| head_kdump.S | ||
| head.S | ||
| install.sh | ||
| ipl_data.c | ||
| ipl_parm.c | ||
| ipl_report.c | ||
| ipl_vmparm.c | ||
| kaslr.c | ||
| machine_kexec_reloc.c | ||
| Makefile | ||
| mem_detect.c | ||
| mem.S | ||
| pgm_check_info.c | ||
| sclp_early_core.c | ||
| startup.c | ||
| string.c | ||
| uv.c | ||
| uv.h | ||
| version.c | ||
| vmlinux.lds.S | ||