On Friday 22 April 2011, John Calixto wrote: > Allows appropriately-privileged applications to send CMD (normal) and > ACMD (application-specific; preceded with CMD55) commands to > cards/devices on the mmc bus. This is primarily useful for enabling the > security functionality built in to every SD card. > > It can also be used as a generic passthrough (e.g. to enable virtual > machines to control mmc bus devices directly). However, this use case > has not been tested rigorously. Generic passthrough testing was only > conducted for a few non-security opcodes to prove the feasibility of the > passthrough. > > Since any opcode can be sent using this passthrough, it is very possible > to render the card/device unusable. Applications that use this ioctl > must have CAP_SYS_RAWIO. > > Security commands tested on TI PCIxx12 (SDHCI), Sigma Designs SMP8652 > SoC, TI OMAP3621 SoC, TI OMAP3630 SoC, Samsung S5PC110 SoC, Qualcomm > MSM7200A SoC. > > Signed-off-by: John Calixto <john.calixto@xxxxxxxxxxxxxx> > Reviewed-by: Andrei Warkentin <andreiw@xxxxxxxxxxxx> The implementation looks good to me now, Reviewed-by: Arnd Bergmann <arnd@xxxxxxxx> I'll leave the final decision whether this is a good feature to have to Chris. I still believe that we should have per-command ioctls for the security feature, but getting there would require someone to implement it, and I'm not going to do that. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
