mirror of
https://github.com/travisgoodspeed/goodwatch
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47 lines
1.2 KiB
C
47 lines
1.2 KiB
C
/*! \file dmesg.c
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\brief Kernel debug message buffer.
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*/
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#include<stdio.h>
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#include<string.h>
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#include "dmesg.h"
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/* These three buffers are declared to be in the .noinit section so
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that a reboot will not wipe the buffer. Because the memory will be
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corrupted when power is lost, we manually wipe the buffer at
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startup if the magic is corrupted or if the index is unreasonable.
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*/
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//! Ought to be 0xdeadbeef except after power loss.
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uint32_t dmesg_magic __attribute__ ((section (".noinit")));
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//! Index within that buffer.
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uint16_t dmesg_index __attribute__ ((section (".noinit")));
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//! DMESG buffer itself.
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char *dmesg_buffer=(char*)0x2400;
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//! Writes a character to the dmesg buffer.
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int putchar(int c){
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dmesg_index++;
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while(dmesg_index>DMESGLEN)
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dmesg_index=dmesg_index-DMESGLEN;
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return dmesg_buffer[dmesg_index]=(char) c;
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}
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//! Clears the dmesg buffer.
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void dmesg_clear(){
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memset(dmesg_buffer, 0, DMESGLEN);
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dmesg_index=0;
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dmesg_magic=0xdeadbeef;
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}
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//! I ain't never initialized a buffer that didn't need initializin'.
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void dmesg_init(){
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if(dmesg_magic!=0xdeadbeef){
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dmesg_clear();
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printf("Zeroed buffer for bad magic.");
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}
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printf("\n\n----\n");
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}
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