1UCALL(2) System Calls Manual UCALL(2)
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6 ucall - call a kernel subroutine from user mode (2BSD)
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9 #include <pdp/psl.h>
10 #include <sys/types.h>
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12 ucall(priority, function, arg0, arg1)
13 int priority, arg0, arg1;
14 caddr_t function;
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17 Ucall causes the processor priority to be set to priority and the spec‐
18 ified kernel function to be called with arguments arg0 and arg1. Pri‐
19 ority is one of PSL_BR0, ..., PSL_BR7. Processor priority is reset to
20 PSL_BR0 when function returns.
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22 Ucall is allowed only if the user is the superuser. It is obviously
23 extremely dangerous if misused. It's only current use is at system
24 boot time to configure system devices by calling device drivers ...
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27 [EPERM] The caller is not the super-user.
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30 autoconfig(8)
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33 No address validations are attempted.
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35 Ucall is unique to the PDP-11 and 2BSD; its use is discouraged.
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393rd Berkeley Distribution January 22, 1987 UCALL(2)