cregit-Linux how code gets into the kernel

Release 4.14 arch/sparc/include/asm/switch_to_64.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __SPARC64_SWITCH_TO_64_H

#define __SPARC64_SWITCH_TO_64_H

#include <asm/visasm.h>


#define prepare_arch_switch(next)		\
do {                                            \
        flushw_all();                           \
} while (0)

	/* See what happens when you design the chip correctly?
         *
         * We tell gcc we clobber all non-fixed-usage registers except
         * for l0/l1.  It will use one for 'next' and the other to hold
         * the output value of 'last'.  'next' is not referenced again
         * past the invocation of switch_to in the scheduler, so we need
         * not preserve it's value.  Hairy, but it lets us remove 2 loads
         * and 2 stores in this critical code path.  -DaveM
         */

#define switch_to(prev, next, last)					\
do {    save_and_clear_fpu();                                           \
	/* If you are tempted to conditionalize the following */	\
	/* so that ASI is only written if it changes, think again. */	\
        __asm__ __volatile__("wr %%g0, %0, %%asi"                       \
        : : "r" (task_thread_info(next)->current_ds));\
        trap_block[current_thread_info()->cpu].thread =                 \
                task_thread_info(next);                                 \
        __asm__ __volatile__(                                           \
        "mov    %%g4, %%g7\n\t"                                         \
        "stx    %%i6, [%%sp + 2047 + 0x70]\n\t"                         \
        "stx    %%i7, [%%sp + 2047 + 0x78]\n\t"                         \
        "rdpr   %%wstate, %%o5\n\t"                                     \
        "stx    %%o6, [%%g6 + %6]\n\t"                                  \
        "stb    %%o5, [%%g6 + %5]\n\t"                                  \
        "rdpr   %%cwp, %%o5\n\t"                                        \
        "stb    %%o5, [%%g6 + %8]\n\t"                                  \
        "wrpr   %%g0, 15, %%pil\n\t"                                    \
        "mov    %4, %%g6\n\t"                                           \
        "ldub   [%4 + %8], %%g1\n\t"                                    \
        "wrpr   %%g1, %%cwp\n\t"                                        \
        "ldx    [%%g6 + %6], %%o6\n\t"                                  \
        "ldub   [%%g6 + %5], %%o5\n\t"                                  \
        "ldub   [%%g6 + %7], %%o7\n\t"                                  \
        "wrpr   %%o5, 0x0, %%wstate\n\t"                                \
        "ldx    [%%sp + 2047 + 0x70], %%i6\n\t"                         \
        "ldx    [%%sp + 2047 + 0x78], %%i7\n\t"                         \
        "ldx    [%%g6 + %9], %%g4\n\t"                                  \
        "wrpr   %%g0, 14, %%pil\n\t"                                    \
        "brz,pt %%o7, switch_to_pc\n\t"                                 \
        " mov   %%g7, %0\n\t"                                           \
        "sethi  %%hi(ret_from_fork), %%g1\n\t"                          \
        "jmpl   %%g1 + %%lo(ret_from_fork), %%g0\n\t"                   \
        " nop\n\t"                                                      \
        ".globl switch_to_pc\n\t"                                       \
        "switch_to_pc:\n\t"                                             \
        : "=&r" (last), "=r" (current), "=r" (current_thread_info_reg), \
          "=r" (__local_per_cpu_offset)                                 \
        : "0" (task_thread_info(next)),                                 \
          "i" (TI_WSTATE), "i" (TI_KSP), "i" (TI_NEW_CHILD),            \
          "i" (TI_CWP), "i" (TI_TASK)                                   \
        : "cc",                                                         \
                "g1", "g2", "g3",                   "g7",               \
                "l1", "l2", "l3", "l4", "l5", "l6", "l7",               \
          "i0", "i1", "i2", "i3", "i4", "i5",                           \
          "o0", "o1", "o2", "o3", "o4", "o5",       "o7");              \
} while(0)

void synchronize_user_stack(void);
void fault_in_user_windows(void);

#endif /* __SPARC64_SWITCH_TO_64_H */

Overall Contributors

PersonTokensPropCommitsCommitProp
David Howells4794.00%125.00%
Kirill V Tkhai12.00%125.00%
Greg Kroah-Hartman12.00%125.00%
David S. Miller12.00%125.00%
Total50100.00%4100.00%
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