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If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner] .TH DEVMAP_ACCESS 9E "Jan 17, 1997" .SH NAME devmap_access \- device mapping access entry point .SH SYNOPSIS .nf #include #include \fBint prefix\fR\fBdevmap_access\fR(\fBdevmap_cookie_t\fR \fIdhp\fR, \fBvoid *\fR\fIpvtp\fR, \fBoffset_t\fR \fIoff\fR, \fBsize_t\fR \fIlen\fR, \fBuint_t\fR \fItype\fR, \fBuint_t\fR \fIrw\fR); .fi .SH INTERFACE LEVEL illumos DDI specific (illumos DDI). .SH ARGUMENTS .ne 2 .na \fB\fIdhp\fR \fR .ad .RS 9n An opaque mapping handle that the system uses to describe the mapping. .RE .sp .ne 2 .na \fB\fIpvtp\fR \fR .ad .RS 9n Driver private mapping data. .RE .sp .ne 2 .na \fB\fIoff\fR \fR .ad .RS 9n User offset within the logical device memory at which the access begins. .RE .sp .ne 2 .na \fB\fIlen\fR \fR .ad .RS 9n Length (in bytes) of the memory being accessed. .RE .sp .ne 2 .na \fB\fItype\fR \fR .ad .RS 9n Type of access operation. Possible values are: .sp .ne 2 .na \fB\fBDEVMAP_ACCESS\fR \fR .ad .RS 18n Memory access. .RE .sp .ne 2 .na \fB\fBDEVMAP_LOCK\fR \fR .ad .RS 18n Lock the memory being accessed. .RE .sp .ne 2 .na \fB\fBDEVMAP_UNLOCK\fR \fR .ad .RS 18n Unlock the memory being accessed. .RE .RE .sp .ne 2 .na \fB\fIrw\fR \fR .ad .RS 9n Direction of access. Possible values are: .sp .ne 2 .na \fB\fBDEVMAP_READ\fR \fR .ad .RS 17n Read access attempted. .RE .sp .ne 2 .na \fB\fBDEVMAP_WRITE\fR \fR .ad .RS 17n Write access attempted. .RE .sp .ne 2 .na \fB\fBDEVMAP_EXEC\fR \fR .ad .RS 17n Execution access attempted. .RE .RE .SH DESCRIPTION The \fBdevmap_access()\fR entry point is an optional routine. It notifies drivers whenever an access is made to a mapping described by \fIdhp\fR that has not been validated or does not have sufficient protection for the access. The system expects \fBdevmap_access()\fR to call either \fBdevmap_do_ctxmgt\fR(9F) or \fBdevmap_default_access\fR(9F) to load the memory address translations before it returns. For mappings that support context switching, device drivers should call \fBdevmap_do_ctxmgt\fR(9F). For mappings that do not support context switching, the drivers should call \fBdevmap_default_access\fR(9F). .sp .LP In \fBdevmap_access()\fR, drivers perform memory access related operations such as context switching, checking the availability of the memory object, and locking and unlocking the memory object being accessed. The \fBdevmap_access()\fR entry point is set to \fINULL\fR if no operations need to be performed. .sp .LP \fIpvtp\fR is a pointer to the driver's private mapping data that was allocated and initialized in the \fBdevmap_map\fR(9E) entry point. .sp .LP \fIoff\fR and \fIlen\fR define the range to be affected by the operations in \fBdevmap_access()\fR. \fItype\fR defines the type of operation that device drivers should perform on the memory object. If \fBtype\fR is either \fBDEVMAP_LOCK\fR or \fBDEVMAP_UNLOCK,\fR the length passed to either \fBdevmap_do_ctxmgt\fR(9F) or \fBdevmap_default_access\fR(9F) must be same as \fIlen\fR. \fIrw\fR specifies the direction of access on the memory object. .sp .LP A non-zero return value from \fBdevmap_access()\fR may result in a \fBSIGSEGV\fR or \fBSIGBUS\fR signal being delivered to the process. .SH RETURN VALUES \fBdevmap_access()\fR returns the following values: .sp .ne 2 .na \fB\fB0\fR \fR .ad .RS 12n Successful completion. .RE .sp .ne 2 .na \fBNon-zero\fR .ad .RS 12n An error occurred. The return value from \fBdevmap_do_ctxmgt\fR(9F) or \fBdevmap_default_access\fR(9F) should be returned. .RE .SH EXAMPLES \fBExample 1 \fR\fBdevmap_access()\fR entry point .sp .LP The following is an example of the \fBdevmap_access()\fR entry point. If the mapping supports context switching, \fBdevmap_access()\fR calls \fBdevmap_do_ctxmgt\fR(9F). Otherwise, \fBdevmap_access()\fR calls \fBdevmap_default_access\fR(9F). .sp .in +2 .nf \&.\|.\|. #define OFF_DO_CTXMGT 0x40000000 #define OFF_NORMAL 0x40100000 #define CTXMGT_SIZE 0x100000 #define NORMAL_SIZE 0x100000 /* * Driver devmap_contextmgt(9E) callback function. */ static int xx_context_mgt(devmap_cookie_t dhp, void *pvtp, offset_t offset, size_t length, uint_t type, uint_t rw) { ...... /* * see devmap_contextmgt(9E) for an example */ } /* * Driver devmap_access(9E) entry point */ static int xxdevmap_access(devmap_cookie_t dhp, void *pvtp, offset_t off, size_t len, uint_t type, uint_t rw) { offset_t diff; int err; /* * check if \fIoff\fR is within the range that supports * context management. */ if ((diff = off - OFF_DO_CTXMG) >= 0 && diff < CTXMGT_SIZE) { /* * calculates the length for context switching */ if ((len + off) > (OFF_DO_CTXMGT + CTXMGT_SIZE)) return (-1); /* * perform context switching */ err = devmap_do_ctxmgt(dhp, pvtp, off, len, type, rw, xx_context_mgt); /* * check if \fI off \fRis within the range that does normal * memory mapping. */ } else if ((diff = off - OFF_NORMAL) >= 0 && diff < NORMAL_SIZE) { if ((len + off) > (OFF_NORMAL + NORMAL_SIZE)) return (-1); err = devmap_default_access(dhp, pvtp, off, len, type, rw); } else return (-1); return (err); } .fi .in -2 .SH SEE ALSO .BR devmap_map (9E), .BR devmap_default_access (9F), .BR devmap_do_ctxmgt (9F), .BR devmap_callback_ctl (9S) .sp .LP \fIWriting Device Drivers\fR